It is important to have proper layout on the
COMHP/N and COMLP/N circuits in order to have the best robust daisy-chain
communication.
- Keep differential traces as short as possible and as
straight as possible. Minimize turns and avoid any looping on the
traces.
- Keep the differential traces on the same layers. Run the
trace in parallel with shielding and matching trace impedance.
- Place the isolation components close to the
connectors.
- When using capacitive isolation, place the high-voltage
capacitor of the COMxP/N pair (where x = H or L) close to each other along
the parallel traces.
- Create a keep-out area (no other traces and no ground
plane) around the daisy-chain components in all PCB layers.