2. Generic routing rules

2.1 Impact of card format: impedance per square

The format of the future board will have a direct impact on the stability of the potential reference. The impedance per square of a copper plane is directly linked to its format beyond the megahertz. Equation (1) gives us the value of the impedance of a square copper plane without holes. At high frequencies, this value is independent of the thickness of the plane. This impedance will be all the more influential for PCBs installed in non-metallic enclosures, as the board manages its equipotentiality on its own. On the other hand, for a board installed in a conductive case, it will be possible to use the case to improve the situation. 3...