PXI-6289 Overvoltage Protection

[CalvinF]

Referencing the PXI-6289

The Datasheet says Device off overvoltage protection is +- 15 V. The  maximum working voltage is 11 volts. The datasheet says we must limit at +-20mA during overvoltage mode.

The question I have, is this, if we zener diode protect at +-15V , do we still need to limit the current to +- 20mA, say with a 750 ohm resistor?

Another way of asking the question, is this: is +-15V considered an overvoltage condition, requiring +-20mA protection?

Thanks

[CalvinF]

bump.

[Tom_W_[DE]]

Hi Calvin-

Yes, you need to protect against both cases (overvoltage and overcurrent).  The voltage protection is only effective up to +-25V (device powered on).  If you exceed that overvoltage protection level or exceed the overcurrent spec during an overvoltage condition (i.e. anything above the working voltage) then device damage may result.  You should ensure that you neither exceed the overvoltage protection maximum nor drive more current than spec'd for the "overpower" condition.

Hopefully this helps-

[CalvinF]

Okay, I still don't know if during the device off condition, rather or not +-15V is considered an "OverVoltage Condition.

[Tom_W_[DE]]

Hi Calvin-

Yes, even when the device is powered off you should be careful to avoid overcurrent conditions.  FYI, any input above the working voltage spec is considered an overvoltage condition.

[CalvinF]

Okay, Thanks for the answer.