{"id":2387,"date":"2026-11-06T09:00:00","date_gmt":"2026-11-06T01:00:00","guid":{"rendered":"https:\/\/www.jingpengpcb.com\/?p=2387"},"modified":"2026-10-08T20:16:15","modified_gmt":"2026-10-08T12:16:15","slug":"pcb-design-final-checks","status":"publish","type":"post","link":"https:\/\/www.jingpengpcb.com\/en\/blog\/pcb-design-final-checks\/","title":{"rendered":"What Elements Should Be Checked During the Final Stages of PCB Design? Package, Routing, and Signal Integrity"},"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>Once a circuit board has been laid out and routed, and both connectivity and spacing are in order, does that mean the design is complete? The answer, of course, is no. In PCB (Printed Circuit Board) design, post-design verification is a critical step that is often overlooked, yet it can help prevent some of the most basic errors, thereby saving time and resources.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"1280\" height=\"720\" class=\"alignnone size-large wp-image-6562\" src=\"https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/what-is-a-circuit-board-counterbore.jpg\" alt=\"What Are Blind Holes in Printed Circuit Boards?\" srcset=\"https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/what-is-a-circuit-board-counterbore.jpg 1280w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/what-is-a-circuit-board-counterbore-300x169.jpg 300w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/what-is-a-circuit-board-counterbore-1024x576.jpg 1024w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/what-is-a-circuit-board-counterbore-768x432.jpg 768w\" sizes=\"auto, (max-width: 1280px) 100vw, 1280px\" \/><\/p>\n<h2>Advanced: There are actually four stages in the post-production review process<\/h2>\n<p>The original text breaks down post-production inspections into six categories: encapsulation, layout, routing, EMC, silk screening, and others. This classification is based on the \u201cinspection targets.\u201d From a different perspective, classifying them by \u201cinspection timing\u201d makes it less likely to overlook any items\u2014post-production inspections should be distributed across four checkpoints:<\/p>\n<div class=\"jp-tw\">\n<table>\n<thead>\n<tr>\n<th>Checkpoint<\/th>\n<th>Timing<\/th>\n<th>Key Inspection Items<\/th>\n<th>The Cost of Missed Detections<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Packaging Checkpoint<\/td>\n<td>When Building and Calling the Database<\/td>\n<td>Pad Size, Hole Diameter, and Screen-Printing Outline<\/td>\n<td>The entire batch cannot be welded<\/td>\n<\/tr>\n<tr>\n<td>Strategic Deployment at Key Passes<\/td>\n<td>When the layout is complete<\/td>\n<td>Module Consolidation, Isolation of Interference Sources, Structural Coordination<\/td>\n<td>Needs to be rearranged<\/td>\n<\/tr>\n<tr>\n<td>Cabling Checkpoint<\/td>\n<td>When the wiring is complete<\/td>\n<td>Current-Carrying Capacity of Line Width, Equal Length of Differential Pairs, and Return Paths<\/td>\n<td>Malfunction, EMI Exceeds Limits<\/td>\n<\/tr>\n<tr>\n<td>Shooting Board Checkpoint<\/td>\n<td>Before Exporting Gerber Files<\/td>\n<td>DRC, Hole Rings, Process Margins, Impedance Table<\/td>\n<td>Factory Rejects, Delay<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<p>The common characteristics of these four checkpoints are:<strong>The earlier the checkpoint, the higher the cost of a missed inspection<\/strong>. If the packaging is wrong, the entire batch is scrapped; if the layout is wrong, it has to be redrawn; whereas if a pre-production inspection uncovers even dozens of minor issues, it usually just requires a single revision to the file.<\/p>\n<ul>\n<li><strong>Packaging Checkpoint<\/strong>: After a new device is added to the database, it must be verified item by item against the datasheet, and a 1:1 physical comparison must be performed;<\/li>\n<li><strong>Strategic Deployment at Key Passes<\/strong>: First, confirm any structural constraints (height limits, no-placement zones, and connector locations), then place the components;<\/li>\n<li><strong>Cabling Checkpoint<\/strong>: Route the critical networks (power, clock, differential) first, then fill in the general signals;<\/li>\n<li><strong>Shooting Board Checkpoint<\/strong>: Use the checklist to check off each item one by one; don't rely on memory.<\/li>\n<\/ul>\n<ol>\n<li>Set up the checkpoints in the order listed above, and proceed to the next step only after completing each checkpoint;<\/li>\n<li>Include the inspection results in the design specifications to facilitate future traceability;<\/li>\n<li>Conduct cross-checks on key items, with a second person verifying the results.<\/li>\n<\/ol>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"1407\" height=\"791\" class=\"alignnone size-large wp-image-8931\" src=\"https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/pcb-layout-design-specification.jpg\" alt=\"PCB Layout Design Specifications\" srcset=\"https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/pcb-layout-design-specification.jpg 1407w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/pcb-layout-design-specification-300x169.jpg 300w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/pcb-layout-design-specification-1024x576.jpg 1024w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/pcb-layout-design-specification-768x432.jpg 768w\" sizes=\"auto, (max-width: 1407px) 100vw, 1407px\" \/><\/p>\n<p>For detailed layout guidelines, see<a href=\"\/en\/blog\/10-circuit-board-design-process-defects\/\">A Summary of 10 PCB Design Process Defects<\/a>; For spacing requirements, see<a href=\"\/en\/blog\/pcb-spacing\/\">Electrical Safety Clearances<\/a>\u3002<\/p>\n<h2>Key Steps in PCB Design<\/h2>\n<p>The design of a PCB involves several key steps, including layout, routing, and component placement. However, completing the design does not guarantee that the circuit board is free of issues. The following are some key elements of post-design verification that help ensure the accuracy and reliability of the design.<\/p>\n<h3>1. Component Packaging<\/h3>\n<h4>a. Pad spacing<\/h4>\n<p>If you are using a new device and creating your own component package, make sure the pad spacing is appropriate. The pad spacing directly affects the quality of the component's soldering.<\/p>\n<h4>b. Via size<\/h4>\n<p>For through-hole components, allow sufficient clearance\u2014typically no less than 0.2 mm\u2014to ensure smooth installation.<\/p>\n<h4>c. Contour screen printing<\/h4>\n<p>It is best to screen-print the device outline slightly larger than its actual size to ensure that the device can be easily installed.<\/p>\n<h2>Advanced: Quantitative Verification Methods for Pad Dimensions<\/h2>\n<p>The original text mentions pad spacing, via margin, and silkscreen outline; all three of these can be further quantified. The core formula for pad design is:<\/p>\n<ul>\n<li><strong>Pad Length<\/strong> = Pin length + extension at both ends; the extension at each end is typically 0.3\u20130.5 mm;<\/li>\n<li><strong>Pad Width<\/strong> = Pin width + offset; for higher densities, use 1.0\u20131.1 times the pin width;<\/li>\n<li><strong>Pad Spacing (Heel-to-Heel)<\/strong>: Leave a solder mask bridge of at least 0.2 mm; otherwise, the risk of solder bridging increases;<\/li>\n<li><strong>Plug Hole Diameter<\/strong> = Maximum pin dimensions + 0.2\u20130.4 mm allowance; for square pins, measure diagonally.<\/li>\n<\/ul>\n<p>Regarding<strong>Fine-pitch components<\/strong>(For example, QFPs and BGAs with 0.4 mm or 0.5 mm pitch), the pad size can no longer be enlarged based on empirical rules. In such cases, the density classifications specified in IPC-7351 should be followed: Density Class A (maximum pad size, suitable for manual soldering), B (standard, recommended for reflow soldering), and C (minimum, for high-density applications). For most mass-production projects, Class B is sufficient.<\/p>\n<ol>\n<li>Obtain the package dimensions diagram from the datasheet and confirm whether the measurements are in metric or imperial units;<\/li>\n<li>Calculate the pad dimensions based on the density grade;<\/li>\n<li>Print a 1:1 drawing and place the actual components on it to compare them visually;<\/li>\n<li>After verifying that everything is correct, enter the items into inventory and note their source and version.<\/li>\n<\/ol>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"800\" height=\"450\" class=\"alignnone size-large wp-image-805\" src=\"https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/06\/pcb-layout-e1691117215111.webp\" alt=\"PCB Layout Services\" 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>For common design mistakes, see<a href=\"\/en\/blog\/common-errors-in-printed-circuit-board-design\/\">How to Avoid Common Mistakes in Printed Circuit Board Design<\/a>; For information on matching boards and packages, see<a href=\"\/en\/capabilities\/pcb-materials\/\">PCB Sheets<\/a>\u3002<\/p>\n<h3>2. Layout<\/h3>\n<h4>a. Location of the IC<\/h4>\n<p>Avoid placing ICs (integrated circuits) near the edges of the circuit board; this helps improve the board's reliability.<\/p>\n<h4>b. Components in the same circuit module<\/h4>\n<p>Place components within the same circuit module close to one another. For example, decoupling capacitors should be placed near the IC\u2019s power pins to ensure proper functionality.<\/p>\n<h4>c. The location and orientation of the outlet<\/h4>\n<p>Based on the actual structure, to facilitate installation, sockets should be positioned according to the principle of proximity\u2014typically near the edge of the circuit board. At the same time, ensure that the sockets are oriented correctly; in particular, for flat-plug sockets, the sockets should face outward from the circuit board.<\/p>\n<h4>d. \"Keep Out\" Area<\/h4>\n<p>Ensure that no components are placed within the \"Keep Out\" area to avoid interfering with other sections.<\/p>\n<h4>e. Location of the interference source<\/h4>\n<p>Keep sources of interference\u2014such as high-speed signals, high-speed clocks, or high-current switching signals\u2014away from sensitive circuits, and use copper planes to isolate them in order to reduce the likelihood of electromagnetic interference.<\/p>\n<h3>3. Wiring<\/h3>\n<h4>a. Line width<\/h4>\n<p>Select an appropriate trace width based on the manufacturing process and current-carrying requirements. The trace width should not be less than the minimum width specified by the PCB manufacturer, which is typically based on a standard of 1 mm per ampere.<\/p>\n<h4>b. Differential signal lines<\/h4>\n<p>For differential signal lines such as USB and Ethernet, ensure that the traces are of equal length, parallel, and in the same plane, and determine the spacing based on impedance requirements.<\/p>\n<h4>c. Return path for high-speed lines<\/h4>\n<p>High-speed traces are prone to generating electromagnetic radiation; when routing them, pay attention to the return paths to avoid electromagnetic interference.<\/p>\n<h4>d. Analog signal lines<\/h4>\n<p>Analog signal lines should be routed separately from digital signal lines, avoid running them near sources of interference, and ensure that the lines are as short as possible.<\/p>\n<h2>Advanced: Wiring inspections can be quantified based on the following criteria<\/h2>\n<p>The original text outlines four principles: trace width, differential pairs, return paths, and analog-digital separation. When translated into a checklist, these can be broken down into the following verifiable items:<\/p>\n<div class=\"jp-tw\">\n<table>\n<thead>\n<tr>\n<th>Checklist Items<\/th>\n<th>Evaluation Criteria<\/th>\n<th>Consequences of Failure to Meet Standards<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Current-carrying line width<\/td>\n<td>Allow a 20%\u201330% margin based on 1 mm\/A (1 oz, 10 \u00b0C temperature rise)<\/td>\n<td>Heat Generation in Wiring, Excessive Voltage Drop<\/td>\n<\/tr>\n<tr>\n<td>Differential Equivalence<\/td>\n<td>Length difference \u2264 5 mil (for high-speed links, as required by the protocol)<\/td>\n<td>Common-mode noise, eye diagram degradation<\/td>\n<\/tr>\n<tr>\n<td>Differential Pair Spacing<\/td>\n<td>Constant throughout, avoiding cross-segmentation<\/td>\n<td>Impedance Change<\/td>\n<\/tr>\n<tr>\n<td>Return Path<\/td>\n<td>The reference plane beneath the signal layer is continuous and uninterrupted.<\/td>\n<td>Increased EMI and Crosstalk<\/td>\n<\/tr>\n<tr>\n<td>The 3W Rule<\/td>\n<td>Center-to-center distance between lines \u2265 3 times the line width<\/td>\n<td>Crosstalk Exceeds the Limit<\/td>\n<\/tr>\n<tr>\n<td>20H Rule<\/td>\n<td>Power-layer indentation \u2265 20 times the interlayer spacing<\/td>\n<td>Edge Radiation<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<p>Among them<strong>The return path is the most easily overlooked yet most critical factor.<\/strong>. High-speed signals do not return along the path of least resistance, but rather along the path of least inductance\u2014that is, the reference plane beneath the signal line. Once the reference plane is slotted or segmented, the return path is forced to take a detour, causing the loop area to increase sharply and simultaneously worsening radiation and crosstalk.<\/p>\n<ul>\n<li><strong>Do not run cables across partitions<\/strong>: If a signal line must cross a planar gap, a coupling capacitor should be added nearby;<\/li>\n<li><strong>Filling Via Holes When Changing Layers<\/strong>: When switching signal reference planes, place ground vias within 100 mils of the via;<\/li>\n<li><strong>Avoid routing at right angles<\/strong>: Changes in trace width at right angles can cause sudden changes in impedance; use 45\u00b0 angles or arcs instead;<\/li>\n<li><strong>Clocking Line Grounding<\/strong>: Add ground traces on both sides and drill ground vias to suppress radiation.<\/li>\n<\/ul>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"768\" class=\"alignnone size-large wp-image-10381\" src=\"https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/pcb-electrostatic-protection-design.jpg\" alt=\"Electrostatic Protection Design for PCBs\" srcset=\"https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/pcb-electrostatic-protection-design.jpg 1024w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/pcb-electrostatic-protection-design-300x225.jpg 300w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/08\/pcb-electrostatic-protection-design-768x576.jpg 768w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/p>\n<p>For more information on signal integrity, see<a href=\"\/en\/blog\/pcb-design-signal-integrity\/\">Signal Integrity Issues in PCB Design<\/a>; For key points on via design, see<a href=\"\/en\/blog\/pcb-spacing\/\">Electrical Safety Clearances<\/a>\u3002<\/p>\n<h3>4. EMC and Signal Integrity<\/h3>\n<h4>a. Termination resistor<\/h4>\n<p>For high-speed or long digital signal lines, a terminating resistor is inserted at the end to improve signal integrity.<\/p>\n<h4>b. Connect a small capacitor in parallel with the input signal line<\/h4>\n<p>For signal lines connected to an interface, connect a capacitor of appropriate size near the interface to reduce interference and maintain signal integrity.<\/p>\n<h4>c. Leadership Skills<\/h4>\n<p>For switch signals with high drive currents, consider using transistors for the drive. For buses with a large number of output ports, buffers can be used for the drive.<\/p>\n<h3>5. Screen Printing<\/h3>\n<h4>a. Board Name, Time, PN Code<\/h4>\n<p>Write the board name, date of manufacture, and product number on the circuit board.<\/p>\n<h4>b. Annotation<\/h4>\n<p>Clearly label the pins or key signals on certain interfaces.<\/p>\n<h4>c. Part Numbers<\/h4>\n<p>Ensure that component markings are placed in the correct locations and avoid placing them over vias.<\/p>\n<h2>Advanced: Thermal design and maintainability should also be included in the final inspection.<\/h2>\n<p>The original six-item checklist focuses primarily on electrical and process aspects, but there are two additional dimensions that should not be overlooked in subsequent inspections:<strong>\u70ed<\/strong>\u4e0e<strong>Maintainability<\/strong>. If there are problems with these two aspects, they often don\u2019t become apparent until the prototype has been in operation for some time.<\/p>\n<ul>\n<li><strong>Distribution of Heating Elements<\/strong>: Do not concentrate power devices in one area to avoid creating localized hot spots;<\/li>\n<li><strong>Heat Dissipation Pathways<\/strong>: Check whether there is an array of heat-dissipation vias beneath the heating element and whether it is connected to the large copper plane on the inner layer;<\/li>\n<li><strong>Thermal Sensor Avoidance<\/strong>: Electrolytic capacitors, crystal oscillators, and other components should be kept away from heat sources;<\/li>\n<li><strong>Testability<\/strong>: Are there test points provided for key signals, and is the spacing compatible with test probes?;<\/li>\n<li><strong>Repairability<\/strong>: Is there sufficient space around the BGA for rework, and are there any components on the underside that might obstruct heating?<\/li>\n<\/ul>\n<p>Heat-dissipating vias are one of the most cost-effective solutions: filling the area beneath the heat sink pads of power devices with vias (typically 0.3 mm in diameter and spaced 0.6\u20130.8 mm apart) to conduct heat to the inner layers or the copper side on the back of the board can significantly reduce junction temperature. It is important to note that the vias must be plugged or filled with resin; otherwise, solder balls and voids may form during soldering.<\/p>\n<h3>6. Other<\/h3>\n<h4>Mark Point<\/h4>\n<p>For PCBs that require machine soldering, add two or three reference marks to ensure accurate positioning.<\/p>\n<h2>Advanced: The Three Key Elements of EMC and Common Remedial Measures<\/h2>\n<p>EMC issues can always be broken down into three key factors:<strong>Interference Sources, Coupling Paths, Sensitive Equipment<\/strong>. When implementing corrective measures, it is sufficient to eliminate any one of these links; however, the costs associated with each are vastly different:<\/p>\n<ul>\n<li><strong>Suppressing Sources of Interference<\/strong>: This is the most thorough and least expensive approach, but it must be implemented during the design phase. Methods include reducing drive strength, adding series resistance, and slowing the rising edge;<\/li>\n<li><strong>Disconnect the coupling path<\/strong>: Most commonly used; methods include ground planes, shielding, filtering, and reducing loop area;<\/li>\n<li><strong>Protecting Sensitive Equipment<\/strong>: As a last resort, measures include adding filter capacitors, TVS diodes, and improving the design to enhance immunity to interference.<\/li>\n<\/ul>\n<p>In actual projects, the typical sequence for rectifying EMC violations is as follows: first, determine whether the violation is due to radiated or conducted emissions; next, identify the frequency points where the limits are exceeded; and finally, trace the interference back to its source. The frequency points are the most valuable clues\u2014<strong>Compare the frequency exceeding the limit to the on-board clock frequency as a multiple<\/strong>...often allows you to pinpoint a specific clock line or switching power supply.<\/p>\n<ol>\n<li>Compare the out-of-specification frequency points with the on-board clock and switching frequency to identify harmonics;<\/li>\n<li>Use a near-field probe to scan and locate radiation hotspots;<\/li>\n<li>Take measures such as blocking, covering, or adjusting drivers in response to hotspots;<\/li>\n<li>Confirm through retesting and document the corrective actions for reference in future projects.<\/li>\n<\/ol>\n<p>It is important to note that during the rectification phase, the solutions are often merely \u201cstopgap measures,\u201d and neither their effectiveness nor their cost-effectiveness compares to the preventive measures taken during the design phase.<strong>Treat EMC as something to consider during the layout and cabling phase<\/strong>... is the fundamental way to avoid repeated corrections down the line.<\/p>\n<h2>Conclusion<\/h2>\n<p>Post-design review is an essential step in PCB design; it helps prevent some of the most basic errors and ensures the reliability and performance of the circuit. Do not overlook this critical step\u2014it will help reduce the amount of work required later on and minimize wasted resources, ensuring that your PCB design proceeds smoothly.<\/p>\n<h2>Advanced: Final Checklist Before Submission<\/h2>\n<p>By consolidating all the check items mentioned above into a pre-production review checklist and checking each item off one by one, you can largely prevent simple mistakes from making their way into the factory:<\/p>\n<div class=\"jp-tw\">\n<table>\n<thead>\n<tr>\n<th>Category<\/th>\n<th>Items for Review<\/th>\n<th>Is it complete?<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Packaging<\/td>\n<td>Verify new component pads against the datasheet; print and compare at a 1:1 scale<\/td>\n<td>\u25a1<\/td>\n<\/tr>\n<tr>\n<td>Layout<\/td>\n<td>Place the IC away from the board edge, place decoupling capacitors near the power pins, and ensure no components are placed in no-route zones.<\/td>\n<td>\u25a1<\/td>\n<\/tr>\n<tr>\n<td>Wiring<\/td>\n<td>Calculation of current-carrying line width, differential isochronality, and continuity of return paths<\/td>\n<td>\u25a1<\/td>\n<\/tr>\n<tr>\n<td>EMC<\/td>\n<td>Interference Source Isolation, Terminating Resistors, Interface Filter Capacitors<\/td>\n<td>\u25a1<\/td>\n<\/tr>\n<tr>\n<td>Screen Printing<\/td>\n<td>Board Name Version, Polarity Markings, Label Clearance from Pads<\/td>\n<td>\u25a1<\/td>\n<\/tr>\n<tr>\n<td>Process<\/td>\n<td>Marking points, process edges, imposition method, sheet thickness tolerance<\/td>\n<td>\u25a1<\/td>\n<\/tr>\n<tr>\n<td>Documents<\/td>\n<td>Gerber Integrity, Drilling Files, Impedance Table, Special Requirements Specifications<\/td>\n<td>\u25a1<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<p>The value of this table lies not in the complexity of its content, but in<strong>Require that inspection procedures be changed from \u201ca quick, experience-based glance\u201d to \u201citem-by-item verification\u201d<\/strong>. In practice, most issues that are sent back for revision involve entries that already exist in the table but were not formally checked at the time.<\/p>\n<ul>\n<li><strong>File Integrity<\/strong>: Missing a Gerber layer or a drill file is the most common low-level error;<\/li>\n<li><strong>Version Consistency<\/strong>: The version numbers of the schematic and PCB must be kept in sync to avoid forgetting to update the board after making changes to the schematic;<\/li>\n<li><strong>Explicit Specification of Special Requirements<\/strong>: Requirements such as impedance, via holes, and gold finger bevels must be specified in the process specifications.<\/li>\n<\/ul>\n<p><img loading=\"lazy\" decoding=\"async\" width=\"800\" height=\"450\" class=\"alignnone size-large wp-image-6393\" src=\"https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/07\/rf-pcb-design.jpg\" alt=\"RF PCB Design\" srcset=\"https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/07\/rf-pcb-design.jpg 800w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/07\/rf-pcb-design-300x169.jpg 300w, https:\/\/www.jingpengpcb.com\/wp-content\/uploads\/2023\/07\/rf-pcb-design-768x432.jpg 768w\" sizes=\"auto, (max-width: 800px) 100vw, 800px\" \/><\/p>\n<p>See our capabilities in high-difficulty board manufacturing<a href=\"\/en\/hdi-pcb\/\">HDI (High-Density Interconnect) Boards<\/a>; For the test plan, see<a href=\"\/en\/pcba-testing\/\">PCBA Testing<\/a>\u3002<\/p>\n<h2>Frequently Asked Questions<\/h2>\n<h3>1. Why are post-design checks so important in PCB design?<\/h3>\n<p>Post-development testing can help avoid some of the most basic errors, ensure the reliability and performance of the circuit, and reduce the need for additional work and waste of resources.<\/p>\n<h3>2. What is a \"Keep Out\" zone?<\/h3>\n<p>A \"Keep Out\" area is a section of a circuit board where components are not allowed to be placed; it is typically used to prevent interference or maintain a safe distance.<\/p>\n<h3>3. Why is it important to stay away from sources of interference?<\/h3>\n<p>Keeping a distance from sources of interference can reduce the likelihood of electromagnetic interference and ensure the proper operation of the circuit.<\/p>\n<h3>4. What is EMC?<\/h3>\n<p><a href=\"\/en\/capabilities\/\">EMC<\/a>(Electromagnetic Compatibility, EMC) refers to the ability of electronic equipment to operate normally in an electromagnetic environment without causing or being subject to interference from other devices.<\/p>\n<h3>5. Why should components and interfaces be labeled?<\/h3>\n<p>Labeling components and interfaces helps identify and troubleshoot problems, thereby improving the efficiency of maintenance and repairs.<\/p>\n<h3>6. Do differential pairs have to be the same length?<\/h3>\n<p>Yes, but the allowable error depends on the signal rate. Low-speed differential signals (such as USB 2.0) allow for length differences of several tens of mils; high-speed serial links typically require the difference to be kept within 5 mils, and this must be compensated within the same section rather than concentrated at the end via a serpentine trace. When routing, be sure to maintain a 3W spacing; otherwise, the compensation section itself will become a source of crosstalk.<\/p>\n<h3>7. How close does a decoupling capacitor have to be to be considered close?<\/h3>\n<p>\u7ecf\u9a8c\u6807\u51c6\u662f\u7535\u5bb9\u5230 IC \u7535\u6e90\u811a\u7684\u8d70\u7ebf\u603b\u957f\u4e0d\u8d85\u8fc7 100 mil\uff08\u7ea6 2.5 mm\uff09\uff0c\u5e76\u4e14\u8981\u5148\u7ecf\u8fc7\u7535\u5bb9\u518d\u5230\u82af\u7247\u5f15\u811a\uff0c\u800c\u4e0d\u662f\u5148\u5230\u5f15\u811a\u518d\u5206\u652f\u5230\u7535\u5bb9\u3002\u9ad8\u9891\u53bb\u8026\uff080.1 \u03bcF \u7ea7\uff09\u6bd4\u4f4e\u9891\u53bb\u8026\uff0810 \u03bcF \u7ea7\uff09\u5bf9\u8ddd\u79bb\u66f4\u654f\u611f\uff0c\u5e94\u4f18\u5148\u4fdd\u8bc1\u5c0f\u7535\u5bb9\u7684\u4f4d\u7f6e\u3002<\/p>\n<h3>8. \u4e3a\u4ec0\u4e48\u8981\u907f\u514d\u76f4\u89d2\u8d70\u7ebf\uff1f<\/h3>\n<p>\u76f4\u89d2\u62d0\u89d2\u5904\u7684\u6709\u6548\u7ebf\u5bbd\u4f1a\u53d8\u5bbd\uff0c\u5bfc\u81f4\u8be5\u70b9\u7279\u6027\u963b\u6297\u4e0b\u964d\uff0c\u5f62\u6210\u963b\u6297\u4e0d\u8fde\u7eed\u70b9\uff1b\u540c\u65f6\u62d0\u89d2\u5916\u4fa7\u7684\u7535\u573a\u96c6\u4e2d\uff0c\u8f90\u5c04\u4e5f\u7565\u9ad8\u3002\u5728 GHz \u7ea7\u4fe1\u53f7\u4e0a\u8fd9\u4e9b\u6548\u5e94\u624d\u660e\u663e\uff0c\u4f4e\u901f\u4fe1\u53f7\u5f71\u54cd\u5f88\u5c0f\u3002\u7528 45\u00b0 \u6216\u5706\u5f27\u62d0\u89d2\u662f\u96f6\u6210\u672c\u7684\u597d\u4e60\u60ef\u3002<\/p>\n<h3>9. \u94fa\u94dc\u4e00\u5b9a\u4f1a\u6539\u5584 EMC \u5417\uff1f<\/h3>\n<p>\u4e0d\u4e00\u5b9a\u3002\u5b9e\u5fc3\u94fa\u94dc\u82e5\u6ca1\u6709\u826f\u597d\u7684\u63a5\u5730\u8fc7\u5b54\u8fde\u63a5\uff0c\u4f1a\u53d8\u6210\u6d6e\u52a8\u5bfc\u4f53\uff0c\u53cd\u800c\u6210\u4e3a\u8f90\u5c04\u5929\u7ebf\u3002\u6b63\u786e\u505a\u6cd5\u662f\u5728\u94fa\u94dc\u533a\u57df\u5747\u5300\u6253\u5730\u8fc7\u5b54\uff08\u95f4\u8ddd\u901a\u5e38\u53d6 \u03bb\/20 \u6216\u6309\u7ecf\u9a8c\u6bcf 100 \u2013 200 mil \u4e00\u4e2a\uff09\uff0c\u8ba9\u94fa\u94dc\u771f\u6b63\u6210\u4e3a\u4f4e\u963b\u6297\u7684\u53c2\u8003\u9762\u3002<\/p>\n<h3>10. Mark \u70b9\u6709\u4ec0\u4e48\u5177\u4f53\u8981\u6c42\uff1f<\/h3>\n<p>\u901a\u5e38\u662f\u76f4\u5f84 1.0 \u2013 1.5 mm \u7684\u88f8\u94dc\u5706\u70b9\uff0c\u8868\u9762\u5904\u7406\u4e0e\u710a\u76d8\u4e00\u81f4\uff0c\u5468\u56f4\u7559\u51fa\u76f4\u5f84 3 mm \u5de6\u53f3\u7684\u65e0\u963b\u710a\u3001\u65e0\u4e1d\u5370\u7a7a\u533a\u4f5c\u4e3a\u80cc\u666f\u5bf9\u6bd4\u3002\u6574\u677f\u81f3\u5c11\u653e 2 \u4e2a\uff08\u5bf9\u89d2\u5206\u5e03\uff0c\u7528\u4e8e\u6821\u6b63\u65cb\u8f6c\uff09\uff0c\u7cbe\u7ec6\u5143\u4ef6\u9644\u8fd1\u53ef\u518d\u52a0\u5c40\u90e8 Mark \u70b9\u3002<\/p>\n<h3>11. \u540e\u671f\u68c0\u67e5\u80fd\u4e0d\u80fd\u9760\u81ea\u52a8\u5316\u5de5\u5177\u5b8c\u6210\uff1f<\/h3>\n<p>\u80fd\u5b8c\u6210\u5927\u90e8\u5206\u3002DRC \u53ef\u4ee5\u68c0\u67e5\u95f4\u8ddd\u3001\u7ebf\u5bbd\u3001\u5b54\u73af\u7b49\u89c4\u5219\u7c7b\u95ee\u9898\uff0cDFM \u5de5\u5177\u53ef\u4ee5\u68c0\u67e5\u53ef\u5236\u9020\u6027\uff0c\u4eff\u771f\u5de5\u5177\u53ef\u4ee5\u8bc4\u4f30\u4fe1\u53f7\u5b8c\u6574\u6027\u4e0e\u7535\u6e90\u5b8c\u6574\u6027\u3002\u4f46\u5c01\u88c5\u4e0e datasheet \u7684\u7b26\u5408\u6027\u3001\u7ed3\u6784\u914d\u5408\u3001\u4e1d\u5370\u53ef\u8bfb\u6027\u8fd9\u7c7b\u95ee\u9898\u4ecd\u9700\u4eba\u5de5\u786e\u8ba4\uff0c\u4e24\u8005\u5e94\u7ed3\u5408\u4f7f\u7528\u3002<\/p>\n<p><strong>Related Processes<\/strong>\uff1a<a href=\"\/en\/blog\/pcb-spacing\/\">Electrical Safety Clearances<\/a> \u00b7 <a href=\"\/en\/blog\/common-errors-in-printed-circuit-board-design\/\">How to Avoid Common Mistakes in Printed Circuit Board Design<\/a><\/p>","protected":false},"excerpt":{"rendered":"<p>\u4e00\u5757\u7535\u8def\u677f\u5b8c\u6210\u4e86\u5e03\u5c40\u5e03\u7ebf\uff0c\u8fde\u901a\u6027\u548c\u95f4\u8ddd\u90fd\u6ca1\u6709\u95ee\u9898\uff0c\u662f\u5426\u5c31\u7b97\u5b8c\u6210\u4e86\u5462\uff1f\u7b54\u6848\u5f53\u7136\u662f\u5426\u5b9a\u7684\u3002\u5728PCB\uff08Printed [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":6562,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"slim_seo":{"title":"What Elements Should Be Checked During the Final Stages of PCB Design? Package, Routing, and Signal Integrity","description":"What elements should be checked during the final design review? This guide clearly explains key inspection points such as pad spacing for component packages, via sizes, silkscreen outlines, and layout. It breaks down the process step by step, from theory to implementation, making it easy for beginners to understand."},"_slim_seo_primary_term_category":0,"_slim_seo_primary_term_post_tag":0,"footnotes":""},"categories":[405,26],"tags":[],"class_list":["post-2387","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-pcb-design","category-blog"],"_links":{"self":[{"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/posts\/2387","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=2387"}],"version-history":[{"count":5,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/posts\/2387\/revisions"}],"predecessor-version":[{"id":19991,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/posts\/2387\/revisions\/19991"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/media\/6562"}],"wp:attachment":[{"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/media?parent=2387"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/categories?post=2387"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/tags?post=2387"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}