A detailed guide to PCB layout design

Guideline for PCB layout

The printed circuit board design is more complex than it first seems. A well-designed PCB layout will have circuitry physically organised to maximise the board’s electrical performance while maintaining complete manufacturability. This requires careful administration of library components, CAD configurations and settings, component location, trace routing, and power distribution system planning (PDN). To add to this, designers of layouts need to make sure their efforts are well documented and that the end output is ready to be integrated into the larger electronics system for which it was created.

This is a lot for engineers, particularly those who have never worked with PCB layout. A complete set of electronic circuit layout rules accessible for reference might be helpful for this process. Standards within the industry and the company will determine the design’s specifics, although layout principles are still necessary to aid engineers throughout the board creation process. Here are some recommendations for the PCB layout that you may use as a starting point for your standards in this area.

• Libraries

Use IPC or manufacturer specs for package sizes when constructing libraries for the PCB layout. However, some pieces may have to be modified because of personal, business, or technological requirements. Footprints in RF designs, for instance, could need narrower pad widths than in a traditional digital design. For more information on creating your custom PCB component footprints, read on!

• • For any library components you create, check the land pattern sizes and spacing to ensure they meet the standard’s requirements.
  • A printed circuit board must include everything from component footprints to silkscreened markings and reference indicators.
  • Before committing to a final design, it’s a good idea to check with your manufacturer to be sure they can produce the components you’re working on.
  • Alternatively, PCB layout footprints from third-party CAD library providers may be used. Some programmes have browsers that make it easy to download manufacturer-built components that are already compatible with your design system.

Power and grounding plan guidelines

Using one or even more continuous flat plates on an interior layer is often the ideal grounding method for current high-speed systems. This offers the highest level of EMI shielding and guarantees unobstructed signal routes, both of which enhance the quality of the sent signal.

You should avoid routing traces through such places if the ground plane is split up on your board because of unusual shapes or features. Your design might generate a lot of extra noise if the signals do not have a continuous and contiguous ground plane to utilise as a clean return channel. Some rules to follow regarding power and ground planes are as follows:

• The ground plane must be physically located next to the signal layers if the board has high-speed routing. This will protect the high-speed cabling from outside influences and provide the signal return lines with a solid grounding.
• Power or ground connections to aircraft need thermal relief pads, which must be maintained with care. The relief pad’s spokes need to be large enough to handle heavy currents without allowing the connections to the pad to function as an absorber plate.
• Careful planning of power connections and divided power planes will provide sufficient power delivery to all components.