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OPA2991: ESD protection diodes for OUTpin.

Part Number: OPA2991
Other Parts Discussed in Thread: OPA991,

Hi team,

I had checked E2Epost.

The OUTpin has ESD diodes.
How much is Vf ?
0.3V or 0.5V?
I'm checking because there is a possibility of undershoot and overshoot.


  • Hi Kengo,

    I repeat what I suggested in the link: Don't use the internal diodes to shunt the over- and undershots to the supply rails but add a BAT54S to the output.


  • Hi Kai,

    Thank you for your comment.
    Measures have already been taken at OUTpin.
    However, I am asking because I want to know the ability value.


  • Hi Kengo,

    why not measuring with a diode tester? Take an unmounted OPA991 and measure the voltage drop between the output and the supply rails and compare it with the voltage drop at the inputs according to figure 7-10 of datasheet.


  • Hi Kengo-san,

    The Vf voltage is approximately 0.5V but can vary. The internal ESD diodes are intended to protect against ESD during manufacturing and handling, not to protect the device against overvoltage.

    If the undershoot/overshoot is caused from something driving the output pin of the OPA2991, external protection must be used.

    Thank you,

    Tim Claycomb