Application: We have a PCBA inside a vehicle's embedded system. The PCBA receives DC voltages from a power input connector. We do have access to signal ground aka 5V_return at the power connector and we have a mounting hole nearby that will be chassis ground. Note chassis ground and signal ground will be isolated on our PCBA, but the may be connected in some manner within the larger system. (Outside the scope of our design)
Plan: Place ESD (Electro-Static Discharge) suppressor (TVS) diodes near the power input connector to protect the voltage rail inputs from sending ESD strikes "downstream" to the various circuits/ICs on-board.
- Is it better to connect the ESD diodes to chassis ground or signal ground?
- Should we use unidirectional or bidirectional diodes?
- Should a more complicated array of diodes be used for better protection? i.e. a diode from +5V to chassis and a diode from GND to chassis?