Answer Happy

(2) (25%) Maximum cutoff frequency fr of MOSFET D + 1 Cust CM 8m Vgs RL 85 I S Consider the above small-signal equivalent circuit including Miller capacitance CM = Cgst(1 + 9mRL) and the gate-source capacitance Cgst, while gm is the transconductance. The cutoff frequency fris defined to be the frequency at which the magnitude of the current gain becomes unity, or when the magnitude of the input current li is equal to the ideal load current Id.
= (a) Verify that 9m 9m fr 210(Cgst + Cm) 270CG where CG is the equivalent input gate capacitance. (10%) (b) For the ideal MOSFET, in the saturation region, Co CoxWL, while gm = Gms, verify that - fr Ims 2πες Mn (VGS - Vr) 21L2 (10%) (c) Assume that un= 400 cm²/V-s, L = 1.2 um, Vr=0.5 V, VGs = 2.2 V, find fr.(5%)