[SOLVED] Can fully differential op amp be connected as buffer?

[jdp721]

Hi.

Can a fully differential op amp be used as a unity-gain buffer, in some manner as we use a single-ended opamp:



If yes, how to connect up the circuit?

 

[Dominik Przyborowski]

With -1 gain, yes. But to make noninverting differential buffer You need FDDA (Fully Differential Difference Amplifier - 4 inputs, 2 outputs)

 

[jdp721]

Hi Dominik (and other members

Can the fully diff opamp be connected like below?



Thanks,
jdp

 

[pankajpc]

Yes, One has to cover rail to rail operation at input and use differential output stage.

 

[erikl]

Can the fully diff opamp be connected like below?
View attachment 108578

No. Connect +out to -in, and -out to +in .

 

[FvM]

No. Connect +out to -in, and -out to +in .

I'm not completely clear about the purpose of this circuit, e.g. where goes the input signal? Analog has suggested a few unusual circuit with fully differential OP in the AD8132 datasheet. They depend in part on the frequency characteristic of the common mode feedback circuit.