Is it possible to use feedback network to change an OTA to a real OpAmp

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bhl777

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Hi All, when I study feedback effect, one of its effect is to reduce the output impedance. Then I am curious, if we have an OTA with high output impedance, is it possible to use feedback to reduce this impedance to a very low level, then this OTA will be a OpAmp? Since we always need output stage to convert OTA to an OpAmp, can we use feedback to realize this target as well?

Thank you!
 

If you compute the output resistance, you can see the effect of feedback (resistive feedback R1-R2):

Rout=Rota||(R1+R2)/(1+gm*R1)

gm: OTA transconductance.

You can see that the OTA output resistance is reduced - however, only by the factor gm*R1.
 
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