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DRV8873-Q1: Inquiry about the impact of applying external 5V to the DVDD pin of DRV8873

ryuichi.a.sakai
Prodigy 100 points
Part Number: DRV8873-Q1
Other Parts Discussed in Thread: DRV8873

Hi experts.

I am writing to inquire about the DRV8873 IC and its DVDD pin. According to the datasheet, it is mentioned that DVDD has an internal regulator.

I would like to confirm if there would be any issues if an external 5V is applied to the DVDD pin. Specifically, I have the following two points that I would like to clarify:

1. What impact would it have on the operation of the IC if an external5V is applied to the DVDD pin?

2. Could applying external 5V to DVDD pin potentially lead to IC failure?

I would greatly appreciate it if you could provide me with any relevant information or guidelines regarding this matter.

  • 0
    TI__Mastermind 44595 points

    Hi Sakai-san,

    Thank you for posting in this forum. Like you pointed out from the datasheet, the device has an integrated LDO for generating DVDD voltage from the VM rail. 

    1. Internal DVDD always guarantees proper power supply sequencing for the digital logic including proper power on reset POR when VM is applied to the device. An external DVDD input would fight against the internal LDO especially if there is voltage difference between them lead to undesired current flow in or out of this pin. The DVDD pin has an absolute min and max rating which must not be violated.

    The internal LDO output itself could vary from 4.7V to 5.3V, device to device and with temperature and operating voltage.

    2. When VM is not powered and external DVDD is applied to the device it may lead to excessive current flow into the device through internal operation and protection circuits and may weaken the device structures eventually leading to failure. When there is difference in voltage between external DVDD input and internal DVDD cross current flow may impact device operation, overheat and may lead to failure. These are the risks. Thank you.

    Regards, Murugavel

  • 0 in reply to Murugavel4637
    Prodigy 100 points

    I designed the wrong circuit. I connected the Vout of an external DCDC converter to the DVDD of DRV8873. The output of the DCDC converter is 5V. Do I need to fix this circuit?

  • 0 in reply to ryuichi.a.sakai
    TI__Mastermind 44595 points

    Hi Sakai-san,

    Is it possible to DNP any component to not feed 5V into the DVDD pin, it just needs capacitor to GND as shown in the datasheet. This should be easy fix. We recommend to fix this. Thanks.

    Regards, Murugavel