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Short ciruit protection fails

Category: Hardware
Product Number: ADA4870

I've got a problem with the short circuit protection.

The schematic is the following (without decoupling and SD, ON and TS for simplicity's sake):

output signal

So I got a single supply setup with +40V VCC and 20V DC offset. I perform the pin configuration outlined in the datasheet (When turning the amplifier back on from the shutdown state, pull the SD pin high and then pull the ON pin low. Following this sequence ensures power-on. Afterwards, the ON pin can be floated to enable short-circuit protection) to enable the amp and the short circuit protection.

When a short occurs the ts-flag drops to approx 300mV - so far so good. After 3-5 s the ADA4870 then is destroyed (smells and the VCC pin is basically shorted on the ADA4870). When I replace the ADA4870 everything works again.

Could it be possible that the 20V DC offset voltage destroys the ADA4870, even though short circuit protection is enabled?

Do I need to add a coupling capacitor Cout at the output as follows?


Or is there another reason, why the short circuit protection fails?

Thanks in advance for any help!

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