TVS Diode at GPIO

[Nishantt]

I take a switch on the P0.19 pin of the nrf52832 IC. So there will be a need of TVS diode for ESD protection at this switch because it will be directly in contact with Human Body. Can you please tell me what parameters I need to select for TVS diode. Specifically what Clamping voltage I need to take for the TVS diode. 

[ketiljo]

There are internal ESD diodes in the GPIO that will handle voltage up to at least 500 V. You will need external protection for inputs that can be touched. Any TVS diode can be uses here. as long as the break down or clamping voltage is higher than the opiating voltage on the pin. Vbr of 5 to 6 V is ok. 

[Nishantt]

Okay. So it is ok to take clamping voltage greater than Absolute maximum ratings of the IC or Pin. Right?
And the reason behind this is because the ESD strike is only for few microseconds and absolute maximum ratings are continues DC voltage.
Please correct me if I am wrong. Thank you.

[ketiljo]

That's correct. The external TVS diode only needs to enhance the ESD level of the device.