OPA4187: Different grounds for power supply and inputs

And what could be the effects if we use like this?

Hi Jai,

can you post the picture again?

Kai

Hi Jai,

a total isolation between the two grounds will not work, because the input bias current of OPAmp flowing out of the VIN pin must find a current path back to GND2.

Kai

Hi Kai,
Basically we need to have isolation between input and output. The
Can you please suggest how we can achieve analog signal isolation

Hi Jai,

you could take one of TI's isolation amplifiers:

www.ti.com/.../products.html

How much isolation do you need? Can you tell more about your apllication?

Kai

Hi Kai,
We have unisolated voltage to OpAMP input and output of apamp is connected to micro controller( which needs to be isolated) and power supply of op amp is isolated one.

Hi Jai,

why do you need isolation? Is there a dangerous high voltage between the two grounds?

Kai

Hi Kai,
We have mainly two sections. One is isolated section and other non-isolated section. Power Isolation is required for ODVA certification and so we are providing.
But whatever the opamp section is there, at that place the input is coming from non isolated section and output should be applied to isolated section.
So, please suggest.

Hello Jai,

Isolation amplifier products are handled on another TI E2E forum so they can best assist you with any circuit details. When I search the TI we site here are some resources I found useful:

You may need to condition the input signal before it proceeds to the isolation amplifier. If that is the case we can assist with recommending precision op amps.

Regards, Thomas

Precision Amplifiers Applications Engineering