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DRV8848: Part getting defective

Ruud den Bekker
Prodigy 210 points
Part Number: DRV8848
Other Parts Discussed in Thread: , TM4C123GH6PM

L.S.,

We are using the BOOST-DRV8848 boosterpack which uses the DRV8848 using the design as given in the part's datasheet.

It's been connected to a switched power supply of 15V, using ONE motor (no load current < 0.5A) on outputs B, driven by a 20kHz PWM signal

from a TM4C123GH6PM.

We have students working with it and a lot are getting defective at a high pace (3 in two days time). Most of them result in

an open output stage (no PWM output anymore)

Any idea what can cause this problem?

What will happen if the power supply is NOT connected (no Vm present) and they are moving the motor by hand?

Will this destroy the output stage?

Regards,

Ruud den Bekker

  • 0
    TI__Genius 14487 points
    Hello Ruud,

    When these failures occurred, did the FAULT light on the board light up? This would indicate an overcurrent condition or a short on the outputs, but the fault should clear when you power cycle the device.

    Other than that, if the board experiences any parameters outside those specified in the Absolute Maximum table in the datasheet, then it may fail. ESD can also cause devices to fail. If the benches do not have proper ESD protection, this is a possible risk. When you are not using the boards, be sure to store them in an ESD bag.

    Spinning the motor by hand while the device is not powered should not be an issue. A small amount of current might flow through the body diodes of the H-bridge, but I don't expect the device to be damaged.
  • 0 in reply to James Lockridge19
    Prodigy 210 points
    Hello James,

    No, the FAULT led did not light up. The output simply gets defective. After replacing it with a new board
    everything worked fine.

    I myself, had one device that shorted between power and ground, but also then the led
    dit not light up, because my power supply limited the output voltage to about 2V (and current @4A!!)

    We asked them not to touch the boards to avoid ESD problems. Today no further board died, but
    I ordered a few axtra ones, just as a precaution. So it's still unknown what causes the problem.