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DRV8860: No DOUT when no load

Shaofeng Luo
Intellectual 1660 points
Part Number: DRV8860

Hi team

Customer encountered some strange case on DRV8860, for some devices, when it's no-load, the DOUT has no output. The schematic is as below, the actual pull-up resistor is 270kohm. Do you have any insight? Thanks!

  • 0
    TI__Mastermind 37683 points

    Hi Shaofeng,

    Are they seeing any data in DOUT of previous devices in the chain? or only at the DOUT of last DRV? 

    What is the value of VCC? 

    DOUT is being measured after which type of command? All available commands listed below. 

    Regards,

    Pablo Armet

  • 0 in reply to Pablo Armet
    TI__Intellectual 1660 points

    Hi Pablo

    The DOUT will stop at the middle DRV8860, like U11 or U12 in the schematic. It's random case. The DOUT is no signal whatever the type of command.

  • 0 in reply to Shaofeng Luo
    TI__Mastermind 37683 points

    Hi Shaofeng,

    What is the VCC voltage? I am asking because the DRV8860 comes with an internal 1.4kΩ pull-up resistor to 5.7V. If external pull-up is different, there will be a conflict of voltage at the DOUT pin. 

    Shaofeng Luo said:
    The DOUT will stop at the middle DRV8860, like U11 or U12 in the schematic. It's random case. The DOUT is no signal whatever the type of command

    So the place where DOUT stops occurs at random? Is it reproducible consistently? Is it seen in multiple boards? Does it function properly with load connected?

    Regards,

    Pablo Armet