PCB (Printed Circuit Board) layout and routing are critical steps in the design of electronic devices, as they directly affect circuit performance and reliability. In this article, we will introduce some basic rules for PCB layout and routing to ensure the proper operation of the circuit board.<\/p>\n
PCB layout should be organized by circuit modules. Circuits with the same function should be grouped into a single module. Within each circuit module, components should be grouped according to the principle of proximity, and digital and analog circuits should be laid out separately.<\/p>\n
Components and devices must not be mounted within 1.27 mm of non-mounting holes, such as alignment holes and standard holes. For M2.5 screws, components must not be mounted within 3.5 mm of the mounting hole; for M3 screws, they must not be mounted within 4 mm.<\/p>\n
Avoid placing vias directly beneath horizontally mounted components such as resistors, inductors (through-hole), and electrolytic capacitors to prevent short circuits between the vias and the component casings after wave soldering.<\/p>\n
The distance between the outer edge of the component and the edge of the board should be at least 5 mm.<\/p>\n
The distance between the outer edge of an SMT component\u2019s pad and the outer edge of an adjacent through-hole component should be greater than 2 mm.<\/p>\n
Metal-enclosed components and metal parts (such as shielding boxes) must not come into contact with other components and must not be placed near printed traces or pads. The distance between them must be greater than 2 mm. The distance from the outer edge of square holes\u2014such as alignment holes, fastener mounting holes, and elliptical holes\u2014on the board to the board edge must be greater than 3 mm.<\/p>\n
Heating elements must not be placed near conductors or heat-sensitive components; in particular, high-heat equipment should be distributed evenly.<\/p>\n
Power sockets should be placed as close as possible to the edges of the printed circuit board, and the terminals of the power sockets should be located on the same side as the busbars to which they are connected. Power sockets and other soldered connectors should not be placed between connectors, in order to facilitate soldering and the design and routing of power cables. The spacing between power sockets and soldered joints should be arranged to allow for easy insertion and removal of power plugs.<\/p>\n
All IC components should be aligned on one side, and the polarity markings on polarized components should be clearly visible. There must be no more than two directions of polarity markings on a single printed circuit board; if there are two directions, they must be perpendicular to each other.<\/p>\n
The trace layout on the board should be appropriately dense. When there are significant variations in density, a copper mesh should be used to fill the gaps, with a mesh size greater than 8 mil (or 0.2 mm).<\/p>\n
There must be no vias on SMD pads to prevent solder paste from flowing out and causing cold solder joints. Critical signal lines must not pass through socket pins.<\/p>\n
Surface-mount components should be aligned on one side only, and the orientation of the characters should match the orientation of the package.<\/p>\n
Polarized components should be oriented as uniformly as possible, with the polarity markings on the same board.<\/p>\n
The distance from the routed trace to the edge of the PCB should be 1 mm or less; routing is not permitted within 1 mm of mounting holes.<\/p>\n
PCB power traces should be as wide as possible, with a minimum width of 18 mil; signal traces must be at least 12 mil wide. For traces connecting to and from the CPU, the trace width must be at least 10 mil (or 8 mil), and the spacing between traces must be at least 10 mil.<\/p>\n
Standard through-holes should not be less than 30 mil.<\/p>\n
For dual through-hole components, use 60-mil pads and 40-mil via diameters. For 1\/4W resistors, the pad size is 51 \u00d7 55 mil (0805 surface-mount); for through-hole mounting, the pad size is 62 mil and the via diameter is 42 mil. For non-polarized capacitors, the specifications are 51 \u00d7 55 mil (0805 surface-mount); when mounted as through-hole components, the pad size is 50 mil and the hole diameter is 28 mil.<\/p>\n
Note that power and ground wires should be arranged in a radial pattern, and signal wires should not form loops.<\/p>\n
These basic rules will help ensure the stability, reliability, and performance of PCBs. Adhering to these rules during the PCB design process will help minimize potential problems and improve the operational efficiency of electronic devices.<\/p>\n
PCB layout and routing are critical steps in the design of electronic devices, as they directly affect circuit performance and reliability. By following the basic rules outlined above, you can ensure that your PCB design is more stable and reliable. At the same time, different electronic devices may have specific requirements, so it is essential to adjust and optimize your PCB design according to those specific needs.<\/p>\n
We hope these guidelines will help you improve your PCB layout and routing, thereby enhancing the quality and performance of your electronic products. If you need further assistance or have any questions, please feel free to contact us.<\/p>\n
1. Why are components and devices organized into circuit modules?<\/p>\n
Breaking circuits down into modules helps organize and manage complex circuits, improving efficiency in maintenance and troubleshooting.<\/p>\n
2. Why should components not be mounted around mounting holes?<\/p>\n
This prevents interference between the components and the mounting holes, ensuring the safety and stability of the components.<\/p>\n
3. Why is it important to ensure the directional consistency of polarizing components?<\/p>\n
Ensuring that polarized components (such as electrolytic capacitors) are oriented correctly guarantees their proper operation and prevents damage caused by reverse connection.<\/p>\n
4. Why should vias be avoided on SMD pads?<\/p>\n
Vias can cause solder paste to leak, which can lead to cold solder joints and connection issues.<\/p>\n
5. Why are power and signal cables arranged in a radial pattern?<\/p>\n
A radial layout helps reduce electromagnetic interference and improve circuit stability.<\/p>","protected":false},"excerpt":{"rendered":"
PCB\uff08Printed Circuit Board\uff09\u5e03\u5c40\u548c\u5e03\u7ebf\u662f\u7535\u5b50\u8bbe\u5907\u8bbe\u8ba1\u4e2d\u81f3\u5173\u91cd\u8981\u7684\u6b65\u9aa4\uff0c\u5b83\u76f4\u63a5\u5f71\u54cd\u5230\u7535\u8def […]<\/p>\n","protected":false},"author":1,"featured_media":8689,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"slim_seo":{"title":"Basic Rules for PCB Routing: Design Guidelines and Best Practices","description":"What are the basic rules for PCB routing? Explain each rule in detail\u2014from modular layout, the distance between mounting holes and the board edge, via clearance, and handling heat-generating components to trace density\u2014and provide a practical checklist that can be followed."},"_slim_seo_primary_term_category":0,"_slim_seo_primary_term_post_tag":0,"footnotes":""},"categories":[26],"tags":[223],"class_list":["post-3829","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog","tag-pcb"],"_links":{"self":[{"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/posts\/3829","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=3829"}],"version-history":[{"count":1,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/posts\/3829\/revisions"}],"predecessor-version":[{"id":19434,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/posts\/3829\/revisions\/19434"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/media\/8689"}],"wp:attachment":[{"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/media?parent=3829"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/categories?post=3829"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.jingpengpcb.com\/en\/wp-json\/wp\/v2\/tags?post=3829"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}