When ESD protection is not needed?

[LauraCx]

When ESD protection is not needed?

0. Summary

This article answers some Frequently Asked Questions about design examples that do not require ESD protection.
 

1. Is it really necessary to provide external ESD protection in case of no ESD
protection for GPIO pins of a microcontroller built in?

It is only necessary to protect GPIO exposed to system-level ESD (connector, button) otherwise embedded HBM is enough.
 

2. How do you protect multiple MCU pins that do not go outside the PCB and is it
necessary? (boards can be completely damaged from accidental touching of a
PCB pad)

PINs that do not go outside the PCB do not require specific ESD protection but special care is mandatory for handling (conductive lab coat with ESD wrist connected to the ground).
 

3. Is external ESD protection needed for CDM (charged device model)?

No, ESD protection according to CDM is granted for all ICs because it is related to component level protection like HBM.