8.55 In the common-gate amplifier circuit of Fig. P8.55, Q2:
and Q3:
are matched. K1n(W/L)n = k1 p(W/L)p = 4 mA/V2, and all transistors have |Vt | = 0.8 V and |VA | = 20 V. The signal vsig is a small sinusoidal signal with no dc component.
(a) Neglecting the effect of VA, find the dc drain current of Q1:
and the required value of VBIAS.
(b) Find the values of gm1 and ro for all transistors.
(c) Find the value of Rin.
(d) Find the value of Rout.
(e) Calculate the voltage gains vo/vi and vo/vsig.
(f) How large can vsig be (peak-to-peak) while maintaining saturation-mode operation for Q1:
and Q2:
