INA3221: INA3221 input voltage when IC is not powered

Kari Malmivirta

Part Number: INA3221

Hi,

we are using INA3221 for voltage monitoring. Input is protected with 24V zener-diode. Current is limited by resistors in the level of mA.

I would like to know what happens if there is no power in VDD, but there might be 24V voltage at the input. Our schematics below, there are +IN and -IN connected in our application.

What kind of ESD-prtotection there is, normal diodes which might leak power to VDD?

Rgds,

-Kari-

6 months ago

+1 Mitch M 6 months ago

TI__Mastermind 19865 points

Hello Kari,

It is actually just fine to have the common mode voltage connected when the device is powered off. Here is the associated section from the datasheet:

Regards,

Mitch

0 Kari Malmivirta 6 months ago in reply to Mitch M

Prodigy 20 points

Hi Mitch,

You are perfectly right! I do not know how I have been able to avoid this text.

Rgds,

-Kari-

0 Kari Malmivirta 6 months ago in reply to Kari Malmivirta

Prodigy 20 points

...and thanks!!!

0 Mitch M 6 months ago in reply to Kari Malmivirta

TI__Mastermind 19865 points

You're welcome! No worries, there's a lot of info in the datasheet, it's easy to miss some things.

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INA3221: INA3221 input voltage when IC is not powered