Shorted between VDD and VSS, what are causes? How can it produce?

[Whanni]

Currently, I design a board with STM32f413 to Motor control. Sometimes, when I turn on the power supply , I have a shorted occurs betwwen VDD (+3.3V) and VSS. So I had to change my CPU to my board. In my board, I have a different power supply betwen my VDD and VDDA.

Do you think a separated power supply can produce a shorted if the VDD and VDDA are not provide at teh same time? Or if there are drop between it?

Thank you,

Best regards,

Wh

[Uwe Bonnes]

I managed to get "hot" STM32 by injecting to much current into some input. I read the datasheet 6.1.7. that as long as every voltage is below 4.0 volt, either VDD or VDDA can be omitted with no harm. Check your layout for: Spikes in VDD(A) when switching, unconnected VDD(A) pins, or pins unintentional connected to voltage > 4 Volt.