STM32H753IIT6 communication failure

[bakhil27024]

Hello,

I am using an STM32H753IIT6 AA184 VQ V TWN AA. It does not communicate when I connect my serial board through serial communication and try to upload a TTL file using TeraTerm. The device is not even detected. However, when I replace the chip, it starts communicating normally. This has happened with multiple units and the result is the same.

We verified that there are no soldering issues—X‑ray scans showed no defects. We have also tested all voltage levels and clock signals according to the datasheet, and everything appears correct.

I am concerned about what might be causing this issue. Could you please help me understand what could be going wrong?

Thank you.

[TDK]

 Based on what you've described, in particular that replacing the chip "fixes" the issue, it seems the chip was damaged. Potentially overvoltage or ESD or some other event.