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OPA333AIDBVR issue

Knighty
Intellectual 380 points
Other Parts Discussed in Thread: OPA333

 

Hi all,

I am facing with OPA333A issue,  pin1 (out) and pin5 (V+) short to ground. Can anyone give comment for the possible roots cause or any reason to make output pin1 and pin5 short to gnd. I have attached the schematic for your reference.

Thanks

  • 0
    TI__Guru* 93105 points

    Hello Knighty,

    Thank you for supplying the OPA333 application schematic. When a pin exhibits a very low resistance to a supply pin such as ground it is sometimes evidence that a catastrophic event has taken place internal to the device. Most often the device pin has been subjected to Electrical Over Stress (EOS) and the safe operating voltage has been exceeded. There is the possibility that the normally off electrostatic discharge (ESD) circuitry was triggered "on" by the EOS event which usually has catastrophic consequences. Once ESD protection circuitry is triggered, or breakdown takes place, low resistance, high current paths are established and excessive internal heating damages the device.

    It sounds from your description that short circuit paths to ground were created from both the output and supply pins to ground. The OPA333 output connects back to the positive supply pin through the normally off ESD diode. The diode can carry high current for a short period of time. If an EOS is applied to the output pin it possible for that EOS to applied to the supply pin as well. You haven't shown what is connected to the output and that circuit may provide some clues. Or there may be an EOS event occurring at the supply pin. I suggest you monitor the supply and output pins on a good, working device with an O-scope as you put the circuit through its paces from start-up to shut-down. Look for any EOS or transient conditions where the device is being subjected to too much voltage.

    Regards, Thomas

    PA - Linear Applications Engineering

  • 0 in reply to Thomas Kuehl
    Intellectual 380 points

    Hi Thomas,

     Thank for your comment, it very helpful. Per your requested, the attaced is outpu of OPA333A connected to MCU. as for the signal of supply pin, I did not see any high transient(normal operating at 3.3V), it operate maximun at 3.3V rms.

     4503.OPA333.xls

     

    Thanks.

    NT

  • 0 in reply to Knighty
    TI__Guru* 93105 points

    Hello NT,

    How many OPA333 failures have you observed in the circuit application? Is the end product in production? Was the failure(s) a field return? Is the device package visibly damaged as a result of the failure?

    If need be we can take this discussion off the E2E forum and use email.

    Thanks, Thomas

    PA - Linear Applications Engineering