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Associate
July 15, 2025
Solved

question about VDD pin

  • July 15, 2025
  • 3 replies
  • 461 views

I'm a beginner and I don't understand the datasheet very well. Can I externally power my STM32 F446RE from the VDD pin (the one opposite E5V in the pinout)?
Sorry for the banality, but I only found info for generic GPIOs.
Dar

Best answer by TDK

Putting 5V on VDD will kill the chip.

3 replies

Andrew Neil
Super User
July 15, 2025

Welcome to the forum.

Please see How to write your question to maximize your chances to find a solution for best results.

What board are you referring to?

 


 

A complex system that works is invariably found to have evolved from a simple system that worked.A complex system designed from scratch never works and cannot be patched up to make it work.
DAR20_01Author
Associate
July 15, 2025

Ciao amico.
Mi dispiace. La scheda è la STM32 Nucleo F446RE 
"https://www.st.com/en/evaluation-tools/nucleo-f446re.html" 

TDK
Super User
July 15, 2025

Download the user manual for the board--it goes into the various power options.

In general, yes, you can apply VDD directly, but ensure you're not backpowering something. The schematic can be downloaded from the board product page. Generally, VDD is powered from the board so providing external power may not do what you want.

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DAR20_01Author
Associate
July 15, 2025

Hi my friend,
You're right, I read the datasheet. I can power it from E5V and Vin. My problem is that I've already connected the Murata 24/5 Output to the VDD pin via a PCB track. This avoids damaging the board by powering it externally.
During the design phase, due to the file transfer, we missed this aspect.
Anyway, thanks guys for the quick replies!

DAR20_01Author
Associate
July 15, 2025

So am I doing any harm by powering with 5V into the Vdd? I've already made the connections (on the PCB) I just want to avoid breaking the board now

TDK
TDKBest answer
Super User
July 15, 2025

Putting 5V on VDD will kill the chip.

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