Translate An opAmp integrator to a OTA-C one?

[Turin231]

I have a fliter that uses OpAmp based integrator. I want to make the same filter but using OTA-C instead of opamps. But I'm confused on the process of doing that. Anyone can help me on how to get the same behavior from the transition from one to an other?In other words translating the RC values in the omAmp version into the OTA version with the same behaviour

OpAmp integrator

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OTA-C integrator

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The ota will be a simple differential pair with resistors as loads.

 

[LvW]

Hi Turin231,

Assuming that the OTA mimics a controlled current source with the transconductance gm the integrator time constant is simply C/gm (as compared with T=RC for an opamp integrator).

 

[Turin231]

And the Gm can be controlled by the resistor load in the differential pair if i'm not mistaken....Thanks for the help....

 

[LvW]

The transconductance is controlled by the bias current IB (as indicated in your circuit diagram).
But be aware of the finite output impedance of the OTA which turns the integrator into a first order lowpass.