henrytqy wrote on Nov 9th, 2011, 11:08pm:Yes, I think so.
In integrated amplifiers if Rc is implemented with a mos transistor,in most cases it is usually place first to better control the resistance of the transistor. Do you know that why "better control"?
Thanks~
Yes, you think correct for a mos resistor. In that case, you want the mos resistor on the left. The resistance is controlled better there because the voltage at the "-" node of the gm2 stage varies only a small amount, thus the gate-source voltage of the mos resistor is relatively independent of the output voltage. On the other hand, the output of gm2 can swing rail-to-rail. If you want the mos resistor on the right side of the cap you need to make it a tgate. For example, if you just use an NMOS it will turn off when the output is low leaving you with no compensation.