cancel
Showing results for 
Search instead for 
Did you mean: 

STSpin32G4 Magic Smokes and Pops when Connected to VM

ianAdom
Associate

Hey y'all!

Sorry if this question is a little silly, I'm pretty new to Electrical Engineering and PCB design (this is my first ever PCB), but I've been having trouble with the board I designed for the STSpin32G4. I've been meaning to use it to do FOC control on a BLDC motor. I've been able to power the board via REG3v3/VDD and VSS at 3.3v just fine (including a blink test), but when I try to power the motor at 9V (using VM and PGND), the chip pops and I get some magic smoke. I replicated the process happening on one of my remaining boards in the video at this link. I've also attached the schematic that I was using, but can't figure out what I did wrong.

Screenshot 2025-08-04 162627.pngScreenshot 2025-08-04 162642.png

Of note: I used all ceramic capacitors except for C21 and C22, they should be parallel lines in the schematic but I messed up when I originally created it, polarity shouldn't matter for those. Also, before posting this I accidentally had each corresponding Boot and Out (1-3) reversed, which on re looking over the datasheet, I realized and fixed, but I don't believe that would cause the issue with the Magic Smoke.

 

Thank you so much for your help!

3 REPLIES 3
TDK
Super User

Are PGND and VSS connected somewhere? I don't see it in the schematic.

If you feel a post has answered your question, please click "Accept as Solution".

I don't believe they are - do they need to be? Both are connect to different grounds (the usb 3.3 power ground and the 9v psu ground). On reading I think that might need to be fixed, but I'm not sure if that caused the smoke?

They're connected in all the references and diagrams I can find. Would be weird for a chip to have two isolated grounds.

If you feel a post has answered your question, please click "Accept as Solution".