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DRV8837C: chip is burned out

jerry gu
Prodigy 230 points
Part Number: DRV8837C

application: bike lock

2 chip is tested ,after 1000-times test,one is burned out.

vm=4.2V,  Iout<550mA

test is bellow: a single cycle

( in1,in2 =01

after 1s ,

in1,in2=11

50us delay,

in1,in2=00

50us delay,

sleep =0 )DRV8837C 烧芯片问题.zip

after burning out the chip, testing the resistence,

the resistence between the VM and GND =1.8 ohm

the resistence between the out1 and GND =1.4 ohm

the resistence between the out2 and GND =1.4 ohm

  • 0
    Prodigy 230 points
    what is the cause of burning ? Can you give me some advices for inproving the problem?
  • 0 in reply to jerry gu
    TI__Guru** 114905 points
    Hi Jerry,

    What is the VM voltage? The most common cause is a voltage spike on VM that exceed the absolute minimum or maximum voltages on OUT1, OUT2, or VM.

    Have you examined the outputs when during the test to ensure there are no violations of absolute maximum voltages?

    Also, is the device entering overcurrent when starting? This can be observed when the in1,in2 = 01. The outputs will drive then enter Hi-Z for approximately 1ms. If this is occurring, the 100nF capacitor across OUT1 and OUT2 may need to be reduced.
  • 0 in reply to Rick Duncan
    Prodigy 230 points

    VM：3.2v-4.2V

    how to estimate the state of overcurrent? How to test? 

  • 0 in reply to jerry gu
    TI__Guru** 114905 points
    Hi Jerry,

    The overcurrent circuit can activate if the current is greater than 1.2A (Iocp) for 1us (Tdeg) typical.

    Removing the 100nF capacitor across the output should help determine if the overcurrent is activated. If it is, the capacitor should be reduced or ferrite beads can be placed in series with the outputs to limit the inrush current of the capacitor.