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

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jdp721

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Hi.

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

200px-Op-Amp_Unity-Gain_Buffer.svg.png

If yes, how to connect up the circuit?
 

Dominik Przyborowski

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With -1 gain, yes. But to make noninverting differential buffer You need FDDA (Fully Differential Difference Amplifier - 4 inputs, 2 outputs)
 
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jdp721

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Hi Dominik (and other members :)

Can the fully diff opamp be connected like below?

buffer fdfc.JPG

Thanks,
jdp
 
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pankajpc

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

FvM

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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.
 

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