ZHCSG69E November 2016 – May 2018 DM505
PRODUCTION DATA.
Protection devices must be placed close to the ESD source which means close to the connector. This allows the device to subtract the energy associated with an ESD strike before it reaches the internal circuitry of the application board.
To help minimize the residual voltage pulse that will be built-up at the protection device due to its nonzero turn-on impedance, it is mandatory to route the ESD device with minimum stub length so that the low-resistive, low-inductive path from the signal to the ground is granted and not increasing the impedance between signal and ground.
For ESD protection array being railed to a power supply when no decoupling capacitor is available in close vicinity, consider using a decoupling capacitor (≥ 0.1 µF) tight to the VCC pin of the ESD protection. A positive strike will be partially diverted to this capacitance resulting in a lower residual voltage pulse.
Ensure that there is sufficient metallization for the supply of signals at the interconnect side (VCC and GND in Figure 7-10) from connector to external protection because the interconnect may see between 15-A to 30-A current in a short period of time during the ESD event.
NOTE
To ensure normal behavior of the ESD protection (unwanted leakage), it is better to ground the ESD protection to the board ground rather than any local ground (example isolated shield or audio ground).