Skip to main content
Chris1
Chris1
Associate II
May 22, 2017
Solved

OPAMP output: VDDA overconsumption

  • May 22, 2017
  • 3 replies
  • 1037 views
Posted on May 22, 2017 at 15:35

The STM32L471 Errata document states that:  An overconsumption can appear on VDDA in the following conditions:

• a voltage VPAD is applied on PA3 or PB0 with VDDA+ 50 mV < VPAD < VDDA + 600 mV 

...

Our application uses PB0 as a GPIO output with a voltage in the range described above.  Is that matching the condition 'a voltage VPAD is applied'?

    This topic has been closed for replies.
    Best answer by Amel NASRI
    Posted on May 24, 2017 at 19:01

    Hello Chris,

    The VDDA overconsumption will occur if these conditions are valid:

    • the voltage input on the used pin (PB0 in your case) is in the range VDDA + 50mV, VDDA + 600mV
    • the temperature is below 0°C

    As you are configuring your GPIO in output mode, you shouldn't be impacted by the limitation described in the errata sheet.

    -Amel

    3 replies

    Chris1
    Chris1Author
    Associate II
    May 23, 2017
    Posted on May 23, 2017 at 16:23

    Restating the question:

    If our application results in voltage on PB0 but the voltage is supplied by the microcontroller, is that a case of 'a voltage VPAD is applied'?

    Our application cannot tolerate an extra mA of current consumption.

    waclawek.jan
    waclawek.jan
    Super User
    May 24, 2017
    Posted on May 24, 2017 at 00:12

    I'm not ST so you might want to get confirmation through conservative channels, but I'd say yes.

    JW

    Chris1
    Chris1Author
    Associate II
    May 24, 2017
    Posted on May 24, 2017 at 16:14

    Thanks, Jan.

    I agree, likely only ST staff can clarify what their statement means.

    waclawek.jan
    waclawek.jan
    Super User
    May 24, 2017
    Posted on May 24, 2017 at 16:26

    I wanted to suggest to (ab)use the comparator somehow as source of output, if it's only a plain GPIO output.

    However, I read the ES and DS and RM last night but couldn't really decipher how to enable that output... Lucke me I don't need to use this chip :)

    ST might want to comment.

    JW

    Amel NASRI
    Amel NASRIBest answer
    Technical Moderator
    May 24, 2017
    Posted on May 24, 2017 at 19:01

    Hello Chris,

    The VDDA overconsumption will occur if these conditions are valid:

    • the voltage input on the used pin (PB0 in your case) is in the range VDDA + 50mV, VDDA + 600mV
    • the temperature is below 0°C

    As you are configuring your GPIO in output mode, you shouldn't be impacted by the limitation described in the errata sheet.

    -Amel

    Chris1
    Chris1Author
    Associate II
    May 24, 2017
    Posted on May 24, 2017 at 19:40

    That's good news.

    Thank you for the clarification.

    Terms & ConditionsAccessibility statement