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OPA2171-Q1: Wil it damage component with unexpected power-up sequence?

a0967664
Prodigy 750 points
Part Number: OPA2171-Q1

Hi,

My customer is using OPA2171-Q1 for sensing application on OBC but there is some unexpected power-up sequence. so, they want to know wether it will be damaged the component or not.

the V+(12V) late after (about max few 100's of ms)  V-(-5V) and +In(about 5V)  are  already established.

Best regards

Joey  

  • 0
    TI__Mastermind 23310 points

    Hi Joey,

    The negative supply coming on before the positive supply isn't inherently too concerning, it's the input coming on before the the positive supply rail that is where more concern is. 

    We have a document that talks about this called the Op Amps with Special Input Protection. The concern is the ESD structure will create a path going from the input to the supply pins, in this case, the positive supply.

    Whether this will cause permanent damage to the device in the long term isn't something I can answer definitely but it could. I would recommend to the customer, if possible, to find a way to make sure the supplies turn on before the input voltages do.

    Best Regards,

    Robert Clifton 

  • 0 in reply to Robert Clifton56
    TI__Prodigy 750 points

    Hi Robert,

    Thank you for your feedback.

    Please review customer circuit with this power sequence and feedback again.

    the OPA2171-Q1 is used for differential to single-end signal between ISO AMP(AMC1311B-Q1) and MCU's ADC.

    Best regards

    Joey

  • 0 in reply to a0967664
    TI__Mastermind 23310 points

    Hi Joey,

    The concerns I still pointed to in my previous post remain applicable here. There's a risk when the state of 12P_CHSS supply is floating or grounded after the input sees a signal applied.

    Best Regards,

    Robert Clifton