How to protect Reset pin of MCU from ESD strikes?
What I think you need to do is make sure that the charge from the ESD pulse does not reach the MCU. You have done all the right things to try and absorb this charge.

However, the charge comes from a capacitor with a very low series resistance so you would need devices with a very low series resistance as well to be able to absorb the transient of the ESD charge. Also these devices need to be fast.

What I would try to do is to prevent the charge to flow into the MCU. So I would add a resistor in series with the MCU's reset pin. The MCU will also have ESD protection inside, this combined with this external series resistor and the components you already have should prevent the ESD pulse from resetting the chip. I would start with a 1 kohm resistor but increase it's value if needed.

As the reset input of your MCU will be high-input impedance the extra resistor will not influence normal performance. But it will increase it's ESD handling capability !







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