let's consider this cascode amplifier (here the reference):
I have the following questions:
1) Is it good as a voltage amplifier or as a transconductance amplifier?
I do not understand it because: - voltage gain is evaluated, so it seems that it is used as a voltage amplifier - when the output resistance is evaluated, we see that it is very high, that is not good for a voltage amplifier. Moreover, I have read in my notes that cascode is used sometimes in order to increase the output resistance in order to have a better behaviour as a current source. But if it is true, I do not understand how can it be a current source, since the load will receive a current which is not equal to the drain current, but to I0 - drain current (except the case in which the load is a short).
2) Do we prefer designing Q1 and Q2 to work in saturation or in triode? And why?