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Marrkinho
Associate II
October 18, 2024
Solved

Output voltage

Wanted to confirm if the input/output voltage is 3.3V or 5V depending on the I/O structure of my pin .

I scoped a PWM signal with the board connected to the PC and on the dedicated pin I see the signal in  mV. I would like to send a higher voltage through that pin by connecting an external power supply then scope it , but I believe is not possible  due to its tolerance and perhaps the fact that I can't power the board anything more than 5V if i'm not wrong . I am a bit of confused on why on the scope I get the signal in mV when powered via USB.

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mƎALLEm
mƎALLEmBest answer
ST Technical Moderator
October 18, 2024

Hello @Marrkinho ,

@Marrkinho wrote:

Wanted to confirm if the input/output voltage is 3.3V or 5V depending on the I/O structure of my pin .

 

Most of the IO pins are Five volt tolerant (FT pins) as input but the voltage level could not exceed VDD as output (max 3.6 V).

SofLit_0-1729244728166.png

Example: 

SofLit_1-1729244788763.png

For 5V output and according to your application, you need a voltage level shifter example: https://www.digikey.com/en/blog/logic-level-shifting-basics

 

 

To give better visibility on the answered topics, please click "Best answer" on the reply which solved your issue or answered your question.
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2 replies

Tesla DeLorean
Tesla DeLorean
Guru
October 18, 2024

Chip is not running at 5V

The pins can only sink/source relatively low amounts of current, you'll need a buffer for relays and motors, for example.

Check output voltage on pin without LOAD

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    mƎALLEm
    mƎALLEmBest answer
    ST Technical Moderator
    October 18, 2024

    Hello @Marrkinho ,

    @Marrkinho wrote:

    Wanted to confirm if the input/output voltage is 3.3V or 5V depending on the I/O structure of my pin .

     

    Most of the IO pins are Five volt tolerant (FT pins) as input but the voltage level could not exceed VDD as output (max 3.6 V).

    SofLit_0-1729244728166.png

    Example: 

    SofLit_1-1729244788763.png

    For 5V output and according to your application, you need a voltage level shifter example: https://www.digikey.com/en/blog/logic-level-shifting-basics

     

     

    To give better visibility on the answered topics, please click "Best answer" on the reply which solved your issue or answered your question.
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