LMV321: Do OPA power on / off duty always

Wayne Chuang

Part Number: LMV321

Some application, we would do duty OPA (LMV321) power-on/off always from +3.3V to V+ / GND to V- like above picture “green”, during 100us OPA power enable and 218us power disable with ~3.1KHz.

Does it have any concern and OPA reliability issue with this operation?

over 1 year ago

0 Ron Michallick over 1 year ago

TI__Guru**** 166686 points

Hello Wayne, welcome to the the TI e2e forums

It is fine to do this when the power up and power down event don't stress. the op amp.

For example, supply over shooting, input or output pins that have capacitors that discharge through the op amp pins.

0 Wayne Chuang over 1 year ago in reply to Ron Michallick

Prodigy 10 points

Hi Ron, Thanks for your replay. Just checking your "input or output pins that have capacitors that discharge through the op amp pins", you mean the OPA has internal capacitors at input/output to help to little suppress over-shooting issue.

0 Ron Michallick over 1 year ago in reply to Wayne Chuang

TI__Guru**** 166686 points

Wayne,

The OPA has internal diodes, external capacitors should not pass high current through the input or output pins.

The green supply waveform has no signs of over / under shoot so that part should be fine.

0 Wayne Chuang over 1 year ago in reply to Ron Michallick

Prodigy 10 points

Got it, thank you, Ron.

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LMV321: Do OPA power on / off duty always