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MSP432P401R: Input mode / Current leakage/ pull up resistor

Bradley Baugh
Prodigy 40 points

Part Number: MSP432P401R

Hi , I'm using p4.6 as an input without internal pullup or pull down, the datasheet states that the max current leakage in input mode is 20nA, however after adding an external pullup 50k ohms, there is about ~2uA of current following into the msp432 input pin?..  is my interpretation correct,  there should only be 20nA of current when the pin is set to high impedance mode. Is there ant special states / registers to set ? I would like to use this in an ultra low power application.

Thanks

  • 0
    TI__Guru 73181 points
    Bradley,
    I think that your understanding is correct. The configuration of the IO as an input can be found in the Datasheet (www.ti.com/.../msp432p401r.pdf ) . Please let me know if you can confirm the digital IO configuration.

    Regards,
    Chris
  • 0 in reply to Chris Sterzik
    Prodigy 40 points

    Hi Chris,

    Thanks for your reply.

    I verified that the pin is configured as an input by looking at the direction register using CCS, I also verified that no pull-up / down is enabled.

    I tested the msp432 launchpad just as a sanity check , added a 47k pullup and configured the pin an an input, measuring the current it was about 300nA,  I'm using an Agilent 34401 to take the measurement.

     Also relating to this question , if  the protection diodes are being enabled in some cases? would expect  the input voltage to clamp to ~ 500mV ?

    Regards,

    Bradley

  • 0 in reply to Bradley Baugh
    TI__Guru 73181 points
    Bradley,
    There is no mechanism to disable or engage the protection circuitry. You would need to exceed the operating conditions to see the voltage clamp. I would not recommend doing this.

    Regards,
    Chris

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