INA281: Current Loop Ground

Ahmed Mostafa1

Part Number: INA281

Hello,

I am using the INA281 to read a current from an external PS that passes through this circuit. The loop for this current terminates in a different ground point than the ground used for the INA281. Does the current loop ground need to be the same ground as the INA281?

When I have the loop ground and INA281 ground isolated, I get the incorrect voltage at the output of the INA281, and when I make the loop ground the same as the INA281 GND, I measure the correct voltage at the output of the INA.

over 2 years ago

+1 Javier Contreras4 over 2 years ago

TI__Mastermind 26735 points

Hello Ahmed,

The INA281 cannot handle to GND that are isolated from each other. If two GND are the same but connected at different points that is fine as long as you do not have the Input Voltage pins go below the potential of the GND pin of the INA281.

If the grounds are isolated you can damage the part as the potential difference between the INA281 GND and input pins are not controlled and can easily exceed the Absolute Maximum Rating in the datasheet. I do not suggest you have those isolated.