INA129-EP: Input voltage before power

Ian Templeton

Part Number: INA129-EP

The application I am designing for requires that an input voltage must be on prior to ±Vcc. Will this damage the chip or will the OVP protect the circuit given the input voltage will always be less than 10VDC? Additionally, other amplifiers will have input voltage and ±Vcc power on simultaneously. Could either of these scenarios damage the chip?

over 2 years ago

0 Clemens Ladisch over 2 years ago

Guru 307020 points

This is OK; the absolute maximum ratings allow ±40 V at the inputs.

0 Ian Templeton over 2 years ago in reply to Clemens Ladisch

Prodigy 40 points

Can you please elaborate why this will not damage the INA129-EP?

0 Clemens Ladisch over 2 years ago in reply to Ian Templeton

Guru 307020 points

The device will not be damaged as long as you stay inside all the absolute maximum ratings.

0 Ian Templeton over 2 years ago in reply to Clemens Ladisch

Prodigy 40 points

Okay thank you. Just out of curiosity what if Vcc was below the non-operational levels, say ±2 VDC and the input was within ±40 V?

+1 Marek Lis over 2 years ago

TI__Guru 65070 points

Ian,

INA129-EP will not be damaged under your conditions because of its +/-40V input overvoltage protection BUT this may NOT be true about other op amps.

Having the input voltage applied before power supply may cause overvoltage on supply pin damaging the part - see below.

Instantaneous floating of the supplies due to sequencing may also lead to damage - see below.

All in all, in order to prevent damage to ICs you need to add TVS on supply pins and limit the input current to 10mA or less by adding an input resistor - see below.

Below I have attached ESD/EOS presentation for your review.

2474.ESD_EOS.pptx

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INA129-EP: Input voltage before power