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DRV8836: DRv8836 detect bad chip

Kenneth Tait
Intellectual 290 points
Part Number: DRV8836
Other Parts Discussed in Thread: DRV8833

Hi,

I have a DRV8836 app running a gear motor, 8.2V about 250-300MA Rsens is .15ohm

One channel used

It has been working ok, but all of a sudden it has died...All inputs look fine, but I'm measuring like .2V on the VINT pin which doesn't seem right.

There is no Fault indication.

Is this chip blown, if so how did this happen..i thought this was protected from shorts and overcurrent?

Puzzled

Ken

  • 0
    TI__Guru** 114905 points
    Hi Ken,

    Can you confirm the device is the DRV8836? The DRV8836 does not have a VINT pin and has a max voltage of 7V.
  • 0 in reply to Rick Duncan
    Intellectual 290 points
    Sorry for the typo!! this is a DRV8833 PW tssop package dual driver
  • 0 in reply to Kenneth Tait
    TI__Guru** 114905 points
    Hi Ken,

    Thanks for the clarification.

    How long has the system been working?
    Was any probing being done to the board/chip at the time?


    Is it possible something could have shorted VINT to GND or VCP to GND?
    The outputs have protections against shorts and overcurrent.
  • 0 in reply to Rick Duncan
    Intellectual 290 points

    Hi Rick,

    It's been working a few months now. Low duty cycle from 2-6 secs off to 1-2 secs on with long lapses, so it is not stressed.

    It was on bench and was probing something else, so may be possible scope probe shorted something, but didn't think so.

    this is a medical app so I'm concerned something is not quite right long term. Would it fail if outputs were shorted while running?

    chip never gets  warm in this app, so not a heat problem.

    Also, on the fault pin, I'm only using 1 channel other is hanging so I'm assuming both channels are ored for fault pin. Is there something I have to do to ensure open channel does cause a spurious fault?

    Thanks

    Ken