For the Common-Drain (source-follower) configuration below: a) Draw the small-signal T-model of the circuit (Include the channel length modulation effect). b) Consider that the MOSFET operates with ID = 1. 111 mA, gm = 1 mA/V and that the channel length modulation effect must be included with λ = 10 mV−1. Find the output resistance Ro and the overall gain Gv?
![(a) For the circuit shown in figure 1(a), find the following [20] i. Vi(s)/Vs(s) ii. Vo(s)/Vi(s) iii. Vo(s)/Vs(s) iv. Draw the magnitude plot for |T(jω)| in dBvs. frequency v. Lower 3 dB cut-off frequency fL vi. Upper 3 dB cut-off frequency fH vii. Bandwidth (b) Consider the n-channel MOSFET amplifier in figure 1(b). ID = 12 kn′W L(VGS − Vt)2, VDD = 5 V, RL = 2 kΩ, kn′WL = 1 mA/V2, Vt = 1 V. You can ignore channel length modulation. CC is the input coupling capacitor. You can assume it is infinitely large. [10] i. Determine the required ratio RA/RB such that the MOSFET gm = 1 mA/V. Remember that gm is defined as ∂ID/∂VGS ii. Draw the small-signal π model for the amplifier iii. Calculate the gain Vout/Vin (for gm = 1 mA/V ) (a) Figure for question 1 (a) (b) Figure for question 1 (b)](https://www.doubtrix.com/uploads/editor/8150094238anUwChKdII.jpg)
![a) [2 marks] Determine the resistances, RI and R2, such that the bias current through the resistors is 1/10 of the drain current. For DC analysis, ignore channel length modulation, and assume that the MOSFET remains in saturation. b) [1 mark] Calculate the values of the small-signal parameters, gm and ro. c) [3 marks] Find the small-signal voltage gains, vx/vsig and vo/vsig. Vtp = −0.3 V, μpCox(W/L) = 1.2 mA/V2 and λ = −0.1 V−1. VSS = 3 V, I = 0.5 mA, Rsig = 2 kΩ, and RL = 10 kΩ.](https://www.doubtrix.com/uploads/editor/0605750369hXOOBxEXOx.png)