STM32H723 device damages after few hours of working, then heats up. Thereafter MCU doesn't gets detected on JTAG. Seen supply and ground gets shorted. Few IOs are showing up short to GND after the damage seen. Could you please help on the issue resolution

[AMeha.1]

Hi, As described in the question, the STM32H723ZG damaging after few hours of working. I have a seperate daughter board for the MCU. The unused IOs on the daughter board are terminated to GND using 1k resistor. After damage, we observed that some of the IOs are showing short to GND. I do not see any higher voltage on the IOs while its working.

When verifying the voltage on the working board, we are observing ~0.7V on few IOs instead of 3.3V. And these are pins among the shorted to GND in the damaged MCUs. Pin 48 is the common in all the 5 damages MCUs which is configured as digital input and the input comes from a comparator output. This comparator output is directly connect to MCU IO without any Current limiting resistor. Will this cause any stress on the IOs?

Need your support in resolving this issue at the earliest.

Regards,

Anand M

[Pavel A.]

Look at your board with a thermovisor or at least IR camera. Find where is a bad spot.

[Tesla DeLorean]

Multiple supplies involved in the design?

You should work this with the FAE out of your local ST sales office, do a design review.

>>Will this cause any stress on the IOs?

Something in your design is clearly exceeding the absolute maximums.

Figure floating grounds, excessive voltages, conducting high currents through the IC..