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

[bhl777]

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!

 

[LvW]

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.