Refer to Fig. 10.31(c). In situations in which Rsig is large, the high-frequency
Chapter 10, Problem 10.81(choose chapter or problem)
Refer to Fig. 10.31(c). In situations in which Rsig is large, the high-frequency response of the source follower is determined by the low-pass circuit formed byRsig and the input capacitance. An estimate of Cin can be obtained by using the Miller approximation to replace Cgs with an input capacitance Ceq = Cgs(1K) where K is the gain from gate to source. Using the low-frequency value of K = gmR L/(1 + gmR L) find Ceq and hence Cin and an estimate of fH .
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