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DRV8837: several DRV8837 can not work in low temperature ?

Tom Liu
Prodigy 10 points
Part Number: DRV8837

Dear ,

       Only several pieces of DRV8837 can not work in low temperature ?

is it quality problem ?  Exchange with good DRV8837, bad board become good board, good board become bad board. 

if it is quality problem, how to handle it ?

  • 0
    TI__Mastermind 21690 points

    Hey Tom,

    Can you elaborate what temperatures?  The device should work within spec down to -40C.

    Did you get the DRV8837 parts from TI store or an Authorized Distributor?

    And have you probed the device inputs and monitored supply voltage/current levels at low temperature?  And checked external components such as capacitor derating due to temperature?  Capacitance can change with temperature causing it to be on the edge of the working range for the device, then device-to-device variation can cause undesired behavior. 

    Best,

    Jacob

  • 0 in reply to Jacob Thompson
    Prodigy 10 points

    Hi Jacob,

             Thank you for your reply first.

    The testing temperatures is -40 degree.

    The DRV8837 parts is from Authorized Distributor.

    Yes, I have probed the device all inputs and monitored supply voltage/current levels at low temperature, they are all proper value.

    I also checked external components such as capacitor, it is same as datasheet.

    Although, the problem is difficult to reproduction, but customer cannot agree this issue.

    Because their product is quality first. Do you have other suggestion or method to let DRV8837 to work in -40 degree.

    I must say that only 5% or even less cannot work at -40 degree. The test may need 3 days to happen just several times.

    Customer product spec is -40 degree to 70 degree. They must make sure -40 degree is ok to use.

  • 0 in reply to Tom Liu
    TI__Mastermind 21690 points

    Hey Tom,

    Can you please post your PCB schematics and layout?  I can review those and see if there is anything to improve.  

    And can you elaborate on what is happening on a bad device as far as the input/output pins go? 

    The part should be able to work 100% indefinitely in -40C, sorry you're having these issues.  I haven't heard of any issues with this device regarding low temperature. 

    Best,

    Jacob

  • 0 in reply to Jacob Thompson
    Prodigy 10 points

    Hi Jacob，

              OK,schematics and layout please check attached picture.

    I checked all power and input output pin status.Detailed is as below:

    MV is 10.7V, VCC is 3.2V. in -40 degree, bad device  only reverse can not work.

    Forward function is ok. IN1 and IN2 input PWM waveform.Waveform please refer the attached picture.

    Please help me.

  • 0 in reply to Tom Liu
    TI__Mastermind 21690 points

    Tom, thank you for the layout and schematic.

    What is the "current-COM1" net?  The GND pin and Thermal Pad of the device should be directly connected to GND.  This is important for voltage levels and thermal dissipation.  

    You could also order a DRV8837EVM and test it on there.  

    I see on your oscilloscope shot that the voltage is 11.58V - the VM recommended max is 11V, and absolute max is 12V.  I wonder if overvoltage events over time are damaging the device.  Can you test at VM of 10V instead? 

    Is this a new design?  You might be interested in a newer device such as DRV8212P or a variant of it.  

    Best,

    Jacob