Hardware Design Notes

Version 1 by Stephane Carrez

This page gives advices that I have collected as a result of my experience in designing and making hardware systems. I do not pretend this is the best practices in the area. I use this as a set of notes to follow when I'm designing a new board.

Schema design

Verify the following items:

  • unused pins
  • connector layout (for routing, evolutions, understanding, isolation)
  • decoupling with capacitors
  • protection of power supply
  • control logic to validate
  • do not neglect the pull up resistors

PCB design

Verify and take care of the following items:

  • global positioning of components. There must be enough space between them so that I can solder, repair them.
  • components should be aligned. This simplifies the power supply routing, the mounting.
  • Ground layout
  • Vcc layout
  • enlarge the width of wires (keep it to the max). I try not to go below 0.4mm (16 mil)
  • enlarge the clearance to the maximum. 0.4mm (16 mil) for wire, 0.25 (10 mil) for pads and wire
  • run the Eagle DRC check with a larger clearance and fix the problems.
  • assign a specific Class for the power supply lines and setup that class with a larger width 0.8mm