This is a small signal problem. Suppose the MOSFETs drawn have ID = 1 mA when VG, = 2.5 V, and Vth = 0.5 V. Suppose the BFI’s drawn have IL. = 1 mA when Vs,. = 0.7 V.
VGL, = 5 V VDD = 1 /di I Vt„ II I II =
VDD
RD = 1 kfl Vo„t
Ay
(a) Derive voltage gain Ay and input impedance Zth assuming Rc
(b) Plot Ay as a function of Rc assuming Rc is attached between Vout and ground.
(c) Rederive Ay and 4, assuming RL co and after swapping the BJT and MOSFET.
R
