Output stages for opamp

[MahmoudHassan]

Hello
Dear all ,
I want to ask about a concept I want to understand, I read about output stages (Like the inverter one ) and I found that we can drive it in linear region to get maximum swing and that the input differential amplifier is designed to give the required gain.
But if we drive the output stage into linear I think that the signal will be distorted at it's maximu voltage as part of signal running at good gain of the output stage and other parts will be run at lower gain at maximum of the signal
so the output final signal will be distorted !! ?

 

[Debdut]

I think if the output stage is ensured to remain in triode region throughout its operating range, then the distortion will be less.
However there will be still distortion due to variation of gm throughout the operating range.

 

[erikl]

I think if the output stage is ensured to remain in triode region throughout its operating range, then the distortion will be less.

I'm sure you thought of saturation region ?

... if we drive the output stage into linear I think that the signal will be distorted at it's maximu voltage as part of signal running at good gain of the output stage and other parts will be run at lower gain at maximum of the signal
so the output final signal will be distorted !! ?

Each amp has its own ICMR and its "undistorted" output range, their limits given by the acceptable distortion limits of the application. In the linear range between these limits, distortion can be reduced by high gain and strong (linear) feedback.