Short-circuit on STM32H743

[jean]

Hello!

I've been working with several STM32 parts since 10 years. I'm working for a company so due to confidentiality I can't share the schematic of the custom PCB, sorry.

On the first batches of a new product, using a STM32H743BI, it appears that some of them (around 2%) have an issue in common : these STM have an internal short-circuit on GND-3V3. That's not a real short circuit, it has a resistance, that can vary from 5ohm to 20ohm. So the package become really hot when being powered by 3V3, and is not working at all.

This short-circuit seems to happen from the factory assembly, or from the first power on, I don't know for the moment. But the other working PCB are shipped to 1000+ customers since several months and no issue has been reported.

So it seems that the STM has a quality problem after (or before) the SMD assembly. We used several STM tray batches # and the issue happen with all.

Also, the STM32H743BI is only connected to 3V3 levels. Changing the part on a board and the issue is fixed.

The most strange is that I never had that kind issue with STM before!

Do you know if there is that kind of quality issue with this H7 technology?

Have a nice day!

Jean

[Sarra.S]

Hello @jean​ 

We used several STM tray batches # and the issue happen with all.

>> Actually I don't think that a quality issue will appear in several STM32 batches...

However, I'm escalating your request internally, but this may take some time before getting an answer.

Best way to handle it is to contact your FAE

[Gokulraj_0115]

Hi, I am also facing a similar issue. I am working with the STM32H753ZI on my PCB. When I download the firmware and initialize the chip, it does not respond to the ST-Link, and VCC and GND are short-circuited. Before downloading, I can read the chip flash via the programmer. Please help with this.

[Billy OWEN]

Hi @jean​ 

The forum moderator had marked your post as needing a little more investigation and direct support. An online support case has been created on your behalf, please stand by for just a moment and you will hear from us.

Regards,

Billy

[LCE]

What's the chip's package?

Especially with BGA layouts and placement / soldering, one slight mistake...

If BGAs, did you do quality control with X-rays?

[jean]

Hello,

Thanks for your answers!

The ref is stm32h743bit6 (package LQFP-208)