Hello I am trying to prove the input linear range of a sat. mosfet is vgs <= 0.2(VGS-VTN). HELP. Assuming the MOSFET is in active mode, id=(kn/2)*(vGS-Vtn)^2 --> id=Id+gm*vgs, gm=2*Id/(VGS-VTN) --> vgs=(id-Id)/gm --> vgs=(id-Id)/(2*Id/(VGS-VTN)) then i am stuck....how do you know how much you can vary the drain current? This is a small signal model btw.