over heat of ESP32

[owen_chen]

Hi :

We made our own ESP32 Core-Board using ESP32-D0WDQ6, Core-Board connecting with another implementation board using 2.54mm pitch Pin Connector, pin connector has all ESP32 IOs.
Recently we encountered few cases which cause ESP32 over heated when we do hot-plug of Core-Board(3v3 of ESP32 remains when plugging), once over-heating occured, ESP32 will be damaged few seconds later.
We do have a TVS diode(SMBJ5.0CA) on 3V3 supply line of ESP32 protecting ESP32 aginst surging voltage of power line. Is that possible one or two IOs of ESP32 encountered surging voltage or ESD some kind of stuff which cause over-heating of ESP32, what is the surging voltage or ESD protection level of ESP32 IOs ?

[ESP_Sprite]

Can you post the schematic of your solution?

The ESD protection is a snapback circuit, but obviously that is not meant to get rid of large currents. In general, I've not heard before of an ESP32 failing in such a way by doing something with the GPIOs... I'm wondering if you have something in your design that allows a negative voltage to be applied in some way to the ESP32, for instance.

[johnabel]

Have you checked those few boards don't have a short causing that before thinking about more esoteric possibilities?

[owen_chen]

Hi:

Sch is attached.

What we found recently is over-heat problem could be fixed by decreasing running freq of ESP32 from 240MHz to 80MHz.

[ESP_Sprite]

That schematic unfortunately is not that helpful, as it does not show the connection between the ESP32 board and the other board you plug it in... assuming this is the culprit (and it sounds like this, as plugging in generates the issue), it's kind-of important to see that as well.