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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

    This topic has been closed for replies.
    Best answer by TDK

    Putting 5V on VDD will kill the chip.

    3 replies

    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?

     


     

    DAR20_01Author
    Explorer
    July 15, 2025

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

    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.

    DAR20_01Author
    Explorer
    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
    Explorer
    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

    TDKAnswer
    Super User
    July 15, 2025

    Putting 5V on VDD will kill the chip.