Improved uncompensated CMOS operational amplifier:

 

Increased output range

 

Q6 and Q7 act as the level shifter from the following schematics:

 

 

Approximate equivalent circuit of improved opamp:

 

Most of opamp applications use the feedback arrangement:

 

 

C_in ... overall capacitance of the input circuit including stray capacitances

 

Input sine wave V(jw) amplified by: -AV(jw)

 

Feedback signal:

 

Negative feedback in a low-frequency range

 

Positive feedback in a high-frequency range

 

Compensation:

Additional design step

To prevent oscillation in feedback amplifiers