settling time in ota

[vinogunasekaran]

Hi, i am doing measurement of settling time for my two stage miller compensated ota. In Phillip Allen , Chapter 6, it is advised to use a step input of smaller value ? And for slew rate, larger step input is suggested. Why is that so?

 

[prestonee]

I think you kind of answered it yourself. If you use a large input delta how do you separate settling of the amplifier with the slew of the amplifier? so to avoid this he suggest using a small input, the loopgain will be used to settle even small changes within the accuracy of the amplifier. I like to see how an amplifier behaves with small changes, in my case 50mV steps with larger changes say 200mV steps.