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DRV8305-Q1: Float PWRGD Pin if MCU Watchdog Not Used in DRV8305N?

Part Number: DRV8305-Q1
Other Parts Discussed in Thread: DRV8350

Hi team,

For DRV8305N, if MCU watchdog is not used, can customer just float PWRGD pin? Will this cause any problem to the device since PWRGD pin has pullup to VCC? 

  • Hi Pengyu,

    I'll look into this and will try to give you a response today/tomorrow after reviewing some information 

    Thanks and Best Regards,
    Andrew

  • Hi Pengyu,

    I looked into this and have the below response: 

    • In the case of the PWRGD pin, it is actually used for at least two purposes: 
      • the first is the MCU watchdog feature, like mentioned
      • the second is that it is also used for VREG_UVLO protection in the VREG version of the device to prevent brown-out conditions on the VREG output regulator 

    In the case where you are using DRV8350N, the 'N' version doesn't have VREG - and instead has a basic voltage reference (VREF) instead

    This means neither of the two purposes above apply, and PWRGD might be ok to float.

    • I'll check with my team on this to confirm 

    Thanks and Best Regards,
    Andrew

  • Hi Andrew,

    Is below confirmed? 

    This means neither of the two purposes above apply, and PWRGD might be ok to float.

    • I'll check with my team on this to confirm 
  • Hi Pengyu,

    Yes - got an answer today from the team, and thank you for reminding me.

    The input I received was that it should be fine to float the PWRGD pin in your case, as it is simply an open drain output and does not have any secondary functions.

    Thanks and Best Regards,
    Andrew