Skip to main content
ckim.2390
Associate II
March 23, 2023
Solved

Question about internal Vref of STPM32 chip

  • March 23, 2023
  • 1 reply
  • 1327 views

STPM32's document DS10272 states that Vref is 1.18V.

0693W00000aJYEEQA4.pngHowever, if you install the "STPM3x Evaluation Software" program provided by ST and select the EVAL-STPM32 board in Configuration, Vref is set to 1.2V.

0693W00000aJY2xQAG.pngwhich value is correct?

In addition, if you look at the list (ppm/C) of Vref Temp Compensation in the "STPM3x Evaluation Software" program, you will see the picture below.

0693W00000aJYDVQA4.png 

It differs from Table8 in document DS10272.

0693W00000aJYDpQAO.pngIs there a reason the two are different?

    This topic has been closed for replies.
    Best answer by Peter BENSCH

    Oops, thanks for pointing that out! Apparently the software has not yet been updated to the new parameters and still shows the parameters of the older revisions of the data sheet.

    You can change the reference voltage from 1.2V to 1.18V in the software.

    The displayed value of the temperature compensation is now indeed incorrect, but the coding of the steps remains the same. If you take this into account, you should still be able to work with the software.

    We ask for forgiveness for the not yet updated software.

    Regards

    /Peter

    1 reply

    Peter BENSCH
    Peter BENSCHBest answer
    Technical Moderator
    March 23, 2023

    Oops, thanks for pointing that out! Apparently the software has not yet been updated to the new parameters and still shows the parameters of the older revisions of the data sheet.

    You can change the reference voltage from 1.2V to 1.18V in the software.

    The displayed value of the temperature compensation is now indeed incorrect, but the coding of the steps remains the same. If you take this into account, you should still be able to work with the software.

    We ask for forgiveness for the not yet updated software.

    Regards

    /Peter

    ckim.2390
    ckim.2390Author
    Associate II
    March 23, 2023

    thank you so much for the answer

    Thanks, my question has been solved.

    STPM3x EVAL BOARD related documents (AN4470, UM2066...) and Metrology library are also written with Vref calculated as 1.2V.