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OPA1642: Failure of OPA 1642

宰 宿澤
Prodigy 20 points
Part Number: OPA1642
Other Parts Discussed in Thread: STRIKE

The OPA 1642 is adopted for this circuit.


Originally we used OP 275, we adopted OPA 1642 for recent lot.
We made 10 units of the same, of which 5 units failed OPA 1642.

After confirming the fault condition
Three pins of Pin 8 + Supply, Pin 5 + INPUT, and Pin 4 - Supply were short-circuited inside the OPA 1642 in 1 unit.
Four units shorted internally between Pin 8 + Supply and Pin 5 + INPUT 2 pins.

In the original OP 275, such trouble has never occurred.
There are also some things replaced by LME 49720, but this has never been broken.

It is mysterious that a failure is occurring only in the unit of OPA 1642.
I want to know the mechanism of failure.

Is OPA 1642 not suitable for this use?
Is there anything to keep in mind when using OPA 1642?

  • 0
    TI__Genius 12340 points
    Hello user4877068,

    I suspect that this an ESD strike on the input of the circuit (PAD1) is causing the input ESD cells on IC1B pin 5 to latch up. A solution to this would be to add TVS diodes from that input to ground, which would divert ESD strikes to ground and protect devices downstream.
  • 0 in reply to Alex Davis
    TI__Genius 12340 points
    Hello user4877068,
    I hope that this solved your issue. I'll go ahead and close this thread. If you feel that this is unresolved or want to provide additional information, feel free to reply below, which will reopen this thread.