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DRV8825: DRV8825 design problem

Qi Liu
Expert 4055 points
Part Number: DRV8825

Hi, support team

My customer has the questions as follow:

I'm using the DRV8825 in a design where I am interfacing to an external microcontroller with a 5 VDC supply.

I/O levels from this microcontroller are similarly 5 V.

The DRV datasheet seems to indicate I can drive the logic-level inputs on the device with 5V logic levels without issue.



I would like to know if a separate 3.3 VDC regulated supply is recommended for the DRV in addition to the V3P3OUT provided, as the datasheet seems to indicate this output can only provide 1 mA.

I would like to use the nFAULT output to directly drive an LED (~5 mA) and I'm not sure if I'm better off just not using the DRV's internal V3P3OUT at all, and providing my own 3.3 VDC source?

Thanks so much.

Best regards,
Yuki

  • 0
    TI__Guru 56650 points

    Hello, Yuki,

    If the LED needs 5mA, I would like to have a separated pull-up source, instead of the V3P3OUT. BTW, since nFault pin allows 5V pull-up source, So, it can be pulled up to the 5V microcontroller's supply.

    Regards,

    Wang Li

  • 0 in reply to Wang5577
    TI__Expert 4055 points

    Hi Wang Li

    Thank you for your kindly reply.

    In that case I will pull the LED connected to nFAULT up to +5V.

    Is it also OK to pull pins DECAY, nSLEEP and nRESET to +5V?

    Thanks.

  • +1 in reply to Qi Liu
    TI__Guru 56650 points

    Hello, Yuki,

    All 7V digital input pins can support 5V pull-up.

    Regards,

    Wang Li