{"id":2453,"date":"2024-11-06T08:33:09","date_gmt":"2024-11-06T00:33:09","guid":{"rendered":"https:\/\/www.jingpengpcb.com\/?p=2453"},"modified":"2026-10-02T19:42:29","modified_gmt":"2026-10-02T11:42:29","slug":"latest-131-pcb-layout-specifications","status":"publish","type":"post","link":"https:\/\/www.jingpengpcb.com\/en\/blog\/latest-131-pcb-layout-specifications\/","title":{"rendered":"131 Essential Guidelines for PCB Layout Design: Design Specifications for Improving Performance and Stability"},"content":{"rendered":"<style>\n.jp-tw{overflow-x:auto;margin:26px 0;-webkit-overflow-scrolling:touch;}\n.jp-tw table{border-collapse:collapse;width:100%;min-width:560px;font-size:15px;line-height:1.65;background:#fff;}\n.jp-tw th,.jp-tw td{border:1px solid #dde3ea;padding:11px 14px;text-align:left;vertical-align:top;}\n.jp-tw thead th{background:#eef2f7;color:#1b2733;font-weight:700;white-space:nowrap;border-bottom:2px solid #c9d3de;}\n.jp-tw tbody tr:nth-child(even){background:#fafbfc;}\n.jp-tw tbody tr:hover{background:#f1f5fa;}\n.jp-tw tbody td:first-child{font-weight:600;color:#1b2733;}\n@media(max-width:767px){.jp-tw table{font-size:14px;min-width:520px;}.jp-tw th,.jp-tw td{padding:9px 11px;}}\n<\/style>\n<p style=\"text-indent: 2em; text-align: left;\">In circuit board design,<a href=\"https:\/\/www.jingpengpcb.com\/en\/faq\/what-is-pcb-layout\/\">PCB Layout<\/a>Quality directly affects a product\u2019s performance and stability. For engineers, mastering PCB layout design specifications not only effectively improves design efficiency but also reduces rework rates and costs.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-805\" src=\"https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/06\/pcb-layout-e1691117215111.webp\" alt=\"PCB Layout Services\" width=\"800\" height=\"450\" srcset=\"https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/06\/pcb-layout-e1691117215111.webp 800w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/06\/pcb-layout-e1691117215111-300x169.webp 300w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/06\/pcb-layout-e1691117215111-768x432.webp 768w\" sizes=\"auto, (max-width: 800px) 100vw, 800px\" \/><\/p>\n<p style=\"text-indent: 2em; text-align: left;\">In this article, we have compiled<strong>131 PCB Layout Design Guidelines<\/strong>...to help you avoid common pitfalls during the design process and ensure the reliability and stability of your circuit boards.<\/p>\n<p style=\"text-indent: 2em; text-align: left;\">Whether you're a beginner or an experienced engineer, these specifications can be a powerful tool for your designs.<\/p>\n<div class=\"jp-tw\">\n<table cellspacing=\"0\" cellpadding=\"0\">\n<tbody>\n<tr class=\"firstRow\" style=\"height: 22px;\">\n<td style=\"border-width: 1px; padding: 5px 10px; border-style: solid;\" width=\"35\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">No.<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">Classified by Body Part<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">Technical Specifications<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 33px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">1<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout Isolation Guidelines: Isolation of high- and low-current circuits, high- and low-voltage circuits, high- and low-frequency circuits, input and output circuits, and digital and analog circuits. The criterion for isolation is a difference of one order of magnitude. Isolation methods include: physical separation and ground isolation.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">2<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">The crystal oscillator should be placed as close to the IC as possible, and the traces should be relatively wide.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">3<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">Grounding the Crystal Oscillator Housing<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">4<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">When clock signals are routed through a connector, the pins on the connector should be surrounded by ground pins.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 33px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">5<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">Provide separate power and ground paths for analog and digital circuits. Whenever possible, widen the power and ground traces for these two sections of the circuit or use separate power and ground planes to reduce the impedance of the power and ground loops and minimize any interference voltages that may occur in those loops.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 33px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">6<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">For a standalone PCB, the analog ground and digital ground can be connected at a single point near the system ground. If the power supply voltages are the same, the power supplies for the analog and digital circuits should be connected at a single point at the power supply input. If the power supply voltages are different, connect a 1\u20132 nF capacitor in parallel near the two power supplies to provide a path for the signal return current between them.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 45px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"45\">\n<p style=\"text-indent: 2em; text-align: left;\">7<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"45\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"45\">\n<p style=\"text-indent: 2em; text-align: left;\">If the PCB is plugged into the motherboard, the power supplies and grounds for the motherboard\u2019s analog and digital circuits must also be separated; the analog ground and digital ground should be connected to the motherboard\u2019s ground points, Power supplies should be connected at a single point near the system ground. If the supply voltages are the same, the power supplies for the analog and digital circuits should be connected at a single point at the power input. If the supply voltages are different, connect a 1\u20132 nF capacitor in parallel between the two power supplies near where they meet to provide a path for signal return current between them.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">8<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">When high-speed, medium-speed, and low-speed digital circuits are used together, they should be assigned to different layout areas on the printed circuit board.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">9<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">Low-level analog circuits and digital logic circuits should be separated as much as possible.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">10<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">When designing multilayer printed circuit boards, the power plane should be located close to the ground plane and placed beneath it.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">11<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">When designing multilayer printed circuit boards, the routing layers should be placed adjacent to a solid metal plane.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 33px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">12<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">When designing multilayer printed circuit boards, separate digital and analog circuits; whenever possible, place them on different layers. If they must be placed on the same layer, remedial measures such as routing grooves, adding ground traces, or using physical barriers can be employed. Analog and digital ground planes and power supplies must be kept separate and must not be mixed.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">13<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">Clock circuits and high-frequency circuits are the primary sources of interference and radiation; they must be housed separately and kept away from sensitive circuits.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">14<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">Be aware of waveform distortion during long-distance transmission<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 33px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">15<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">The best way to reduce the loop area between the interference source and the sensitive circuit is to use twisted-pair and shielded cables, twisting the signal wires together with the ground wire (or current-carrying circuit) so that the distance between the signal and the ground wire (or current-carrying circuit) is as short as possible.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">16<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">Increase the distance between the wires to minimize mutual inductance between the interference source and the affected line as much as possible.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">17<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">If possible, route the lines from the interference source at a right angle (or close to a right angle) to the lines being affected; this can significantly reduce coupling between the two lines.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">18<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">Increasing the distance between traces is the best way to reduce capacitive coupling.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">19<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; background: yellow; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; background: yellow; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">Before beginning the actual cabling, the first step is to categorize the cables. The primary method of categorization is by power level, with cables grouped into several categories based on 30 dB increments in power level.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">20<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">Wires of different categories should be bundled separately and laid apart from one another. Wires of adjacent categories may be grouped together after implementing measures such as shielding or twisting. The minimum distance between wire harnesses laid by category is 50\u201375 mm.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 33px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">21<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">When laying out resistors, the gain-control resistors and bias resistors (pull-up and pull-down) in amplifier, pull-up\/pull-down, and regulated rectifier circuits should be placed as close as possible to the amplifier, active components, and their power supply and ground to minimize their decoupling effects (and improve transient response).<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">22<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">Place the bypass capacitor near the power supply input.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">23<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; background: yellow; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; background: yellow; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">Decoupling capacitors should be placed at the power supply input, as close as possible to each IC.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 90px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"90\">\n<p style=\"text-indent: 2em; text-align: left;\">24<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"90\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"90\">\n<p style=\"text-indent: 2em; text-align: left;\">Basic Characteristics of PCBs Impedance: Determined by the mass of the copper and the cross-sectional area. Specifically: 1 ounce = 0.49 milliohms per unit area   Capacitance: C = EoErA\/h, where Eo is the permittivity of free space, Er is the permittivity of the PCB substrate, A is the area through which the current flows, and h is trace spacing   Inductance: Distributed evenly throughout the trace, approximately 1 nH\/m   For 1-ounce copper traces on a 0.25 mm (10 mil) thick FR4 substrate, located above the ground plane, a 0.5 mm wide, 20 mm long trace can produce an impedance of 9.8 milliohms, an inductance of 20 nH, and a coupling capacitance of 1.66 pF between the trace and ground.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 33px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">25<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">Basic Guidelines for PCB Routing: Increase the spacing between traces to reduce crosstalk caused by capacitive coupling; route power and ground lines in parallel to optimize PCB capacitance; route sensitive high-frequency lines away from high-noise power lines; Widen power and ground traces to reduce their impedance;<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">26<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">Separation: Use physical separation to reduce coupling between different types of signal lines, especially between power lines and ground lines.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 33px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">27<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">Local Decoupling: Decouple local power supplies and ICs by using high-capacity bypass capacitors between the power supply input and the PCB to filter low-frequency ripple and meet peak power requirements. Use decoupling capacitors between the power supply and ground of each IC, placing these capacitors as close to the pins as possible.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">28<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">Trace Separation: Minimize crosstalk and noise coupling between adjacent traces on the same layer of the PCB. Apply the 3W standard to critical signal paths.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">29<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">Protection and Bypass Circuits: Implement a two-sided ground protection measure for critical signals, and ensure that both ends of the protection circuit are grounded.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">30<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; background: yellow; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">Single-layer PCB: Ground traces should be at least 1.5 mm wide, and changes in the width of jumpers and ground traces should be kept to a minimum.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">31<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; background: yellow; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">Double-layer PCBs: Preferably use a ground grid or dot matrix layout, with a width of at least 1.5 mm. Alternatively, place the ground on one side and the signal and power traces on the other.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">32<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; background: yellow; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">Protective Loop: Form a loop using the ground wire to enclose and isolate the protective logic.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 33px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">33<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Capacitance: On multilayer boards, PCB capacitance arises from the thin insulating layers between the power plane and the ground plane. Its advantages include very high frequency response and low series inductance that is uniformly distributed across the entire surface or along the entire trace. It is equivalent to a decoupling capacitor uniformly distributed across the entire board.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 33px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">34<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">High-speed and low-speed circuits: High-speed circuits should be routed close to the ground plane, while low-speed circuits should be routed close to the power plane.   Copper fill for ground: Copper fill must ensure proper grounding.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 45px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"45\">\n<p style=\"text-indent: 2em; text-align: left;\">35<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"45\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"45\">\n<p style=\"text-indent: 2em; text-align: left;\">The routing directions of adjacent layers should be orthogonal to each other, and different signal lines should not be routed in the same direction on adjacent layers to reduce unnecessary interlayer crosstalk; When this situation is difficult to avoid due to board structural limitations (such as certain backplanes), particularly at higher signal speeds, consider using ground planes to isolate each routing layer and using signal lines to isolate individual signal lines;<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">36<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">Wiring with one end left floating is not permitted, to avoid the \u201cantenna effect.\u201d<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 45px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"45\">\n<p style=\"text-indent: 2em; text-align: left;\">37<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"45\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"45\">\n<p style=\"text-indent: 2em; text-align: left;\">Impedance Matching Design Rules: The trace width within the same grid should remain consistent. Variations in trace width can cause non-uniformity in the characteristic impedance of the line, which can lead to reflections at high transmission speeds; this situation should be avoided during design. Under certain conditions, variations in trace width may be unavoidable; in such cases, the effective length of the inconsistent sections should be minimized as much as possible.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">38<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">Prevent signal lines from forming self-loops between different layers, as self-loops can cause radiated interference.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">39<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">Short-Circuit Rules: Keep wiring as short as possible, especially for critical signal lines such as clock lines; be sure to place the oscillator very close to the components.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">40<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">Chamfering Rules: In PCB design, sharp angles and right angles should be avoided, as they create unnecessary radiation and result in poor manufacturability. The angle between any two lines should be greater than 135 degrees.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">41<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">The wires connecting the filter capacitor pads to the connection plate should be 0.3 mm in diameter, and the interconnect length should be \u22641.27 mm.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 33px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">42<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">Generally, the high-frequency section is placed at the interface to minimize the length of the wiring. It is also important to consider the separation of the ground planes for the high- and low-frequency sections; typically, the ground planes for the two sections are separated and then connected at a single point at the interface.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 33px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">43<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">In areas with a high density of through-holes, care must be taken to avoid connecting cutouts in the power and ground planes, as this would segment the plane and compromise its integrity, thereby increasing the loop area of signal lines in the ground plane.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 45px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"45\">\n<p style=\"text-indent: 2em; text-align: left;\">44<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"45\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"45\">\n<p style=\"text-indent: 2em; text-align: left;\">Guidelines for Avoiding Overlapping Power Planes: For PCBs with two or more layers, different power planes should not overlap spatially. This is primarily to reduce interference between different power sources, especially between those with significantly different voltages. Overlapping power planes must be avoided whenever possible; when this is unavoidable, consider inserting an intermediate ground layer.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 33px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">45<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">3W Rule: To reduce crosstalk between lines, ensure that the spacing between them is sufficiently large. When the center-to-center distance between lines is at least three times the line width, the electric fields of 70% lines will not interfere with each other. To prevent interference between the electric fields of 98% lines, apply the 10W rule.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">46<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">20H Rule: Using one H (the thickness of the dielectric between the power source and ground) as a unit, retracting by 20H will confine the electric field of the 70% within the grounded edge, while retracting by 1000H will confine the electric field of the 98% within the grounded edge.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 33px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">47<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">The 5-5 Rule: A guideline for selecting the number of layers in a printed circuit board. If the clock frequency reaches 5 MHz or the pulse rise time is less than 5 ns, the PCB must be a multilayer board. If a two-layer board is used, it is best to designate one side of the board as a complete ground plane.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 67px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"67\">\n<p style=\"text-indent: 2em; text-align: left;\">48<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"67\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"67\">\n<p style=\"text-indent: 2em; text-align: left;\">Mixed-Signal PCB Zoning Guidelines: 1. Divide the PCB into separate analog and digital sections; 2. Place A\/D converters across both sections; 3. Do not split the ground plane; establish a unified ground plane beneath both the analog and digital sections of the board; 4. On all layers of the PCB, digital signals must be routed only in the digital section of the board, and analog signals must be routed only in the analog section of the board; 5. Separate the analog power supply from the digital power supply; 6. Tracing must not cross the gap between power supply planes; 7. Signal lines that must cross the gap between power supply planes must be routed on a layer adjacent to a large ground plane; 8. Analyze the actual paths and modes through which return ground currents flow;<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">49<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">Multilayer boards are an effective design measure for board-level EMC protection and are recommended as the preferred option.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">50<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">Signal circuits and power supply circuits should each have their own independent ground wires, which ultimately connect to a single common ground; the two should not share a common ground wire.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">51<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">The signal return path must use a separate, low-impedance grounding circuit; the chassis or structural framework must not be used as part of the circuit.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">52<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">For equipment operating in the medium- and short-wave bands, when connected to ground, the ground wire length must be less than 1\/4\u03bb; if this requirement cannot be met, the ground wire length must not be an odd multiple of 1\/4\u03bb.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">53<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">The ground wires for strong and weak signals must be routed separately and connected to the grounding grid at only one point each.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 78px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"78\">\n<p style=\"text-indent: 2em; text-align: left;\">54<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"78\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; background: yellow; padding: 5px 10px;\" width=\"377\" height=\"78\">\n<p style=\"text-indent: 2em; text-align: left;\">In general, equipment should have at least three separate ground lines: one for low-level circuits (known as the signal ground), one for relays, motors, and high-level circuits (known as the interference ground or noise ground); a third is the safety ground wire of the AC power supply, which must be connected to the equipment chassis ground when the equipment uses AC power; the chassis must be insulated from the power outlet, but both must be connected at a single point, and finally, all ground wires must be gathered at a single point and grounded. Circuit breakers should be grounded at a single point at the location of maximum current. When f  10 MHz, use multi-point grounding; when 1 MHz &lt; f &lt; 10 MHz, if the ground wire length is &lt; 1\/20\u03bb, use single-point grounding; otherwise, use multi-point grounding.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">55<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">Guidelines for Avoiding Ground Loops: Power cables should be routed parallel to ground wires.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">56<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">The heat sink must be connected to the power ground, shield ground, or protective ground on the circuit board (preferably the shield ground or protective ground) to reduce radiated interference.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">57<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; background: yellow; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">Separate digital ground from analog ground, and widen the ground trace<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">58<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">When using a mix of high, medium, and low speeds, pay attention to the different layout areas.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">59<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">Dedicated neutral wire; the routing width of the power cord must be \u22651 mm<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">60<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">Keep the power and ground lines as close together as possible, and arrange the power and ground traces on the entire printed circuit board in a \u201cwell\u201d pattern to ensure an even distribution of current.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">61<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">Whenever possible, route the interference source lines at right angles to the lines subject to induction.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">62<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">When classified by power rating, wires in different categories should be bundled separately, and the distance between separately laid wire harnesses should be 50\u201375 mm.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">63<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">In applications with high performance requirements, the inner conductor must be fully enclosed in a 360\u00b0 wrap, and a coaxial connector must be used to ensure the integrity of the electric field shielding.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">64<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">Multilayer PCBs: The power plane and ground plane must be adjacent. High-speed signals should be routed close to the ground plane, while non-critical signals should be routed close to the power plane.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">65<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; background: yellow; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">Power Supply: When a circuit requires multiple power supplies, isolate each power supply from the others by grounding them separately.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">66<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; background: yellow; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">Vias: For high-speed signals, vias introduce inductance of 1\u20134 nH and capacitance of 0.3\u20130.8 pF. Therefore, vias in high-speed traces should be kept as small as possible. Ensure that the number of vias in parallel high-speed traces is consistent.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">67<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">Stub Lines: Avoid using stub lines on high-frequency and sensitive signal lines.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">68<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">Star-Configuration Signal Layout: Avoid using this for high-speed and sensitive signal lines<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">69<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">Radiating Signal Layout: Avoid using this layout for high-speed and sensitive circuits; maintain a consistent signal path width; and do not place vias too densely when crossing power and ground planes.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">70<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">Ground Loop Area: Keeping the signal path and its ground return trace close together will help minimize ground loops.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 33px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">71<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">Clock circuits are generally placed at the center of the PCB or in a well-grounded location, so that the clock is as close as possible to the microprocessor and the leads are kept as short as possible; at the same time, only the case of the quartz crystal oscillator should be grounded.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">72<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">To further enhance the reliability of the clock circuit, the clock area can be isolated by using ground traces to enclose it, and the ground plane area beneath the crystal oscillator can be enlarged to prevent the routing of other signal lines through it;<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 33px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">73<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">The principles of component layout involve separating analog and digital circuit sections, high-speed and low-speed circuits, high-power and small-signal circuits, and noisy and non-noisy components. At the same time, component leads should be kept as short as possible to minimize mutual interference and coupling.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 33px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">74<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">The circuit board is divided into zones based on function, with the ground lines of each zone connected in parallel and grounded at a single point. When there are multiple circuit units on the board, each unit should have an independent ground path, and all units should be connected to the common ground at a single point. Both single-sided and double-sided boards should use a single-point connection to the power supply and a single-point ground connection.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">75<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">Signal lines should be as short and thick as possible, with protective ground connections on both ends. When signals need to be routed out, use flat cables and arrange them in an alternating \u201cground\u2014signal\u2014ground\u201d pattern.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">76<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; background: yellow; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">Place I\/O interface circuits and power driver circuits as close to the edge of the printed circuit board as possible.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">77<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; background: yellow; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">In addition to clock circuits, try to avoid routing traces near noise-sensitive devices and circuits as much as possible.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 33px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">78<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">When a printed circuit board (PCB) includes high-speed data interfaces such as PCI and ISA, care must be taken to route the circuits on the board progressively according to signal frequency\u2014that is, starting from the slot interface, route high-frequency circuits first, followed by medium-frequency circuits, and then low-frequency circuits\u2014so that circuits prone to generating interference are kept away from the data interface.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">79<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">Signal traces on printed circuit boards should be as short as possible; they should not exceed 625px in length, and the number of vias should be kept to a minimum.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">80<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">When signal lines need to turn, use 45-degree or curved bends in the routing and avoid 90-degree bends to minimize reflections of high-frequency signals.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">81<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; background: yellow; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">Avoid 90-degree bends when routing cables to reduce high-frequency noise emissions.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">82<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; background: yellow; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">Pay attention to the crystal oscillator wiring. Place the crystal oscillator as close as possible to the microcontroller pins, isolate the clock area with a ground plane, and ground and secure the crystal oscillator package.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">83<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">Divide the circuit board into appropriate zones, such as strong and weak signals, and digital and analog signals. Keep sources of interference (such as motors and relays) as far away as possible from sensitive components (such as microcontrollers).<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 33px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">84<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; background: yellow; padding: 5px 10px;\" width=\"377\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">Use ground lines to isolate the digital and analog sections; the digital ground and analog ground must be separated and ultimately connected to the power supply ground at a single point. The routing of A\/D and D\/A chips also follows this principle; manufacturers have already taken this requirement into account when assigning pin layouts for A\/D and D\/A chips.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">85<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; background: yellow; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">The ground lines for microcontrollers and high-power devices should be grounded separately to minimize mutual interference. Place high-power devices as close to the edge of the circuit board as possible.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">86<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; background: yellow; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">When wiring, minimize the area of the loop to reduce induced noise.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">87<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">When wiring, use the thickest possible power and ground wires. In addition to reducing voltage drops, this is especially important for minimizing coupled noise.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">88<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">ICs should be soldered directly onto the circuit board whenever possible; use IC sockets sparingly.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">89<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">Reference points should generally be placed at the intersection of the left and bottom edge lines (or the intersection of their extensions) or at the first pad on the printed circuit board's plug-in component.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">90<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">We recommend using a 25-mil grid for the layout.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">91<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">Keep the total length of the connections as short as possible, and make the critical signal lines as short as possible.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">92<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">Components of the same type should be aligned in the X or Y direction. Discrete components of the same type that have polarity should also be aligned in the X or Y direction whenever possible to facilitate production and debugging;<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 33px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">93<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">Components should be placed in a way that facilitates debugging and maintenance. Small components should not be placed next to large ones, and there should be sufficient space around components that require debugging. Heat-generating components should have sufficient space to facilitate heat dissipation. Thermosensitive components should be kept away from heat-generating components.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 45px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"45\">\n<p style=\"text-indent: 2em; text-align: left;\">94<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"45\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"45\">\n<p style=\"text-indent: 2em; text-align: left;\">The distance between dual-in-line through-hole components must be &gt;2 mm. The distance between a BGA and adjacent components must be &gt;5 mm. The distance between small surface-mount components, such as resistors and capacitors, must be &gt;0.7 mm. The distance between the outer edge of a surface-mount component\u2019s pad and the outer edge of an adjacent through-hole component\u2019s pad must be &gt;2 mm. Through-hole components must not be placed within 5 mm of crimped components. Surface-mount components must not be placed within 5 mm of the solder side.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">95<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">Decoupling capacitors for integrated circuits should be placed as close as possible to the chip\u2019s power pins, with the principle being to place them as close as possible to the high-frequency signals. This ensures the shortest possible path between the power supply and ground.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">96<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">Bypass capacitors should be evenly distributed around the integrated circuit.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">97<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">When laying out components, components that use the same power supply should be placed as close together as possible to facilitate future power supply segmentation.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">98<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">The placement of reactive components used for impedance matching should be arranged appropriately based on their characteristics.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">99<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">When placing capacitors and resistors for termination, it is important to clearly understand their intended use. For multi-load termination, the termination must be placed at the farthest end of the signal path.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">100<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">When placing matching resistors, they should be placed close to the signal's drive end, typically no more than 500 mils away.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">101<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">Adjust the characters so that none of them extend beyond the board edges. Ensure that the character information remains clearly visible after assembly, and that all characters are aligned in both the X and Y directions. The size of the characters and silk-screen printing must be consistent.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">102<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">Prioritize Critical Signal Lines: Give priority to routing critical signals such as power, small-signal analog, high-speed signals, clock signals, and synchronization signals;<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 67px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"67\">\n<p style=\"text-indent: 2em; text-align: left;\">103<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"67\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"67\">\n<p style=\"text-indent: 2em; text-align: left;\">Rule of Minimum Loop Area: The loop area formed by a signal line and its return path should be as small as possible. The smaller the loop area, the less radiation is emitted, and the less external interference is received. In double-sided board design, after reserving sufficient space for the power supply, the remaining area should be filled with reference ground, and necessary vias should be added to effectively connect the signals on both sides. Ground isolation should be used as much as possible for critical signals. For designs operating at higher frequencies, special consideration must be given to signal loop issues on other planes; it is recommended to use multilayer boards.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 45px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"45\">\n<p style=\"text-indent: 2em; text-align: left;\">104<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"45\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"45\">\n<p style=\"text-indent: 2em; text-align: left;\">Rule of Thumb for Ground Leads: Keep ground leads as short as possible and use thicker wires (especially in high-frequency circuits). For circuits operating at different voltage levels, do not use long common ground lines.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">105<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">When connecting internal circuits to a metal enclosure, use a single-point ground to prevent discharge current from flowing through the internal circuits.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">106<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">Components sensitive to electromagnetic interference must be shielded to isolate them from components or circuits that generate electromagnetic interference. If such circuits must run near these components, they should be routed at a 90\u00b0 angle to them.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">107<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">The wiring layer should be positioned adjacent to the solid metal plane. This arrangement is intended to create a flux cancellation effect.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">108<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">Numerous loops are formed between ground points; the diameter of these loops (or the distance between ground points) should be less than 1\/20 of the wavelength at the highest frequency.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 33px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">109<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">On single-sided or double-sided printed circuit boards, the power and ground traces should be placed as close together as possible. The best approach is to route the power traces on one side of the board and the ground traces on the other side, with the two layers aligned vertically; this minimizes the power trace impedance.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">110<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">Signal traces (especially high-frequency signals) should be kept as short as possible.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 56px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"56\">\n<p style=\"text-indent: 2em; text-align: left;\">111<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"56\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"56\">\n<p style=\"text-indent: 2em; text-align: left;\">The distance between two conductors must comply with the provisions of electrical safety design codes, and the voltage difference must not exceed the breakdown voltage of the air or insulating medium between them; otherwise, an electric arc will be generated. Within a time span of 0.7 ns to 10 ns, the arc current can reach tens of amperes, and in some cases may even exceed 100 amperes. The arc will persist until the two conductors come into contact and short-circuit, or until the current drops to a level too low to sustain the arc. Examples of situations where spike arcs may occur include contact with a hand or a metal object; care must be taken to identify these during the design process.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">112<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">Add a ground plane immediately adjacent to the double-sided board, and connect this ground plane to the ground point on the circuit at the shortest possible distance.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">113<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">Ensure that each cable entry point is no more than 40 mm (1.6 inches) from the bottom of the chassis.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">114<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">Connect both the connector housing and the metal switch housing to the chassis ground.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">115<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">Place a wide conductive protective ring around the membrane keyboard, and connect the outer edge of the ring to the metal chassis\u2014or at least to the metal chassis at the four corners. Do not connect this protective ring to the PCB ground.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 33px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">116<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">Use multilayer PCBs: Compared to double-sided PCBs, ground planes, power planes, and tightly spaced signal-to-ground traces can reduce common-mode impedance and inductive coupling to between 1\/10 and 1\/100 of that found in double-sided PCBs. Whenever possible, position each signal layer adjacent to a power plane or ground plane.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 33px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">117<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">For high-density PCBs that have components on both the top and bottom surfaces, very short trace lengths, and extensive ground fills, internal layers can be used. Most of the signal traces, as well as the power and ground planes, are located on the internal layers, thereby functioning similarly to a Faraday cage.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">118<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">Place all connectors on one side of the circuit board whenever possible.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 33px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">119<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">On all PCB layers directly beneath the connectors leading out of the chassis (which are susceptible to direct ESD strikes), place a wide chassis ground or a polygonal ground fill, and connect them together with vias spaced approximately 13 mm apart.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">120<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">When assembling a PCB, do not apply any solder to the mounting hole pads on the top or bottom layers. Use screws with built-in washers to ensure tight contact between the PCB and the metal chassis, shielding layer, or ground plane.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">121<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">On each layer, an identical \u201cisolation zone\u201d must be established between the chassis ground and the circuit ground; if possible, maintain a spacing of 0.64 mm (0.025 inches).<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 101px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"101\">\n<p style=\"text-indent: 2em; text-align: left;\">122<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"101\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"101\">\n<p style=\"text-indent: 2em; text-align: left;\">Set up a ground ring around the circuit to prevent ESD interference: 1. Place a ground ring around the entire perimeter of the circuit board; 2. The width of the ground ring on all layers must be &gt;2.5 mm (0.1 inch); 3. Connect the ground ring with vias every 13 mm (0.5 inch); 4. Connect the ground ring to the common ground of the multilayer circuit; 5. For double-sided boards mounted in a metal enclosure or shielded device, connect the ground ring to the circuit\u2019s common ground; 6. For unshielded double-sided circuits, connect the ground ring to the enclosure ground; Do not apply solder mask to the ground ring so that it can act as an ESD discharge path; include at least one 0.5 mm wide (0.020 inch) gap at some location on the ground ring (on all layers) to prevent the formation of large ground loops; 7. If the circuit board will not be placed inside a metal enclosure or shielding device, do not apply solder mask to the top and bottom layer ground traces on the board, so that they can serve as discharge paths for ESD arcs.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">123<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">In areas that could be directly struck by ESD, a ground trace must be routed near each signal line.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">124<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">Circuits susceptible to ESD should be placed in the center of the PCB to minimize the likelihood of being touched.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">125<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">When the length of a signal line exceeds 300 mm (12 inches), be sure to route a ground wire parallel to it.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 56px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"56\">\n<p style=\"text-indent: 2em; text-align: left;\">126<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"56\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"56\">\n<p style=\"text-indent: 2em; text-align: left;\">Connection guidelines for mounting holes: They may be connected to the circuit\u2019s common ground or isolated from it. 1. When a metal bracket must be used in conjunction with a metal shield or chassis, a 0\u03a9 resistor must be used to establish the connection. 2. Determine the size of the mounting holes to ensure reliable installation of metal or plastic brackets. Use large pads on both the top and bottom layers of the mounting holes; do not apply solder mask to the bottom-layer pads, and ensure that the bottom-layer pads are not soldered using the wave soldering process.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">127<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">Shielded and unshielded signal lines must not be arranged in parallel.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">128<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">Routing guidelines for reset, interrupt, and control signal lines: 1. Use high-frequency filtering; 2. Route them away from input and output circuits; 3. Route them away from the edges of the circuit board.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 14px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">129<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"14\">\n<p style=\"text-indent: 2em; text-align: left;\">The circuit boards inside the chassis are not installed in the openings or along the internal seams.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 22px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">130<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"22\">\n<p style=\"text-indent: 2em; text-align: left;\">Place the circuit boards that are most sensitive to static electricity in the center, where they are less likely to be touched by hand; place the components that are sensitive to static electricity in the center of the circuit boards, where they are less likely to be touched by hand.<\/p>\n<\/td>\n<\/tr>\n<tr style=\"height: 33px;\">\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; padding: 5px 10px;\" width=\"56\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">131<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"145\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">PCB Routing and Layout<\/p>\n<\/td>\n<td style=\"border-width: 1px; border-style: solid; border-top-color: initial; border-left-color: initial; padding: 5px 10px;\" width=\"377\" height=\"33\">\n<p style=\"text-indent: 2em; text-align: left;\">Guidelines for bonding two metal blocks: 1. Solid bonding strips are preferable to braided bonding strips; 2. The bonding area must be free of moisture and standing water; 3. Use multiple conductors to connect the ground planes or ground grids of all circuit boards inside the chassis; 4. Ensure that the width of the bonding points and washers is greater than 5 mm.<\/p>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<p>Every detail of PCB layout design affects the product\u2019s final performance, and these 131 design guidelines are key to improving the stability and performance of the circuit board.<\/p>\n<p>In practical applications, please apply these guidelines flexibly, taking into account project requirements and design objectives to find the most suitable solution.<\/p>\n<p>We hope this information will help you optimize your design process and create even better products. If you have any PCB design needs in this area, please contact us.<a href=\"\/en\/contact\/\">Jingpeng Electronics Experts<\/a>, We're always here to help with your project.<\/p>","protected":false},"excerpt":{"rendered":"<p>\u5728\u7535\u8def\u677f\u8bbe\u8ba1\u4e2d\uff0cPCB Layout\u7684\u8d28\u91cf\u76f4\u63a5\u5f71\u54cd\u5230\u4ea7\u54c1\u7684\u6027\u80fd\u548c\u7a33\u5b9a\u6027\u3002\u5bf9\u4e8e\u5de5\u7a0b\u5e08\u800c\u8a00\uff0c\u638c\u63e1PCB Layou [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":805,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"slim_seo":{"title":"131 Essential Guidelines for PCB Layout Design: Design Specifications for Improving Performance and Stability","description":"What are the design specifications for PCB layout? We\u2019ve compiled 131 design guidelines covering component placement, routing, power and ground, and reliability to help engineers reduce prototyping rework rates and revision costs."},"_slim_seo_primary_term_category":0,"_slim_seo_primary_term_post_tag":0,"footnotes":""},"categories":[26],"tags":[131],"class_list":["post-2453","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog","tag-pcb-layout"],"_links":{"self":[{"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/posts\/2453","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/comments?post=2453"}],"version-history":[{"count":3,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/posts\/2453\/revisions"}],"predecessor-version":[{"id":13371,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/posts\/2453\/revisions\/13371"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/media\/805"}],"wp:attachment":[{"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/media?parent=2453"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/categories?post=2453"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/tags?post=2453"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}