Question

4. (20 pts) - Design the CS stage below for a voltage gain of 6, an input impedance of 100 k12, and a power budget of 5 mW. Assume a voltage drop of 500 mV across Rs. _VoD = 2V un cox = 200MA/v2 VTH = 0.5V ovout =0 Vin Ri, Rz, Ro. Rs. Z ?

Answer 1

Ans:- Given that, Av = 6 , Rín = 100K-12 , P = 5mW Voltage drop of Rs is 0.5V., V7H = 0.5V * Assume MOSFET is in saturation Region. ise. VGS Z VTH & Vos > VGS - VTH. :: VG 2 Vs + VTH = 0.5 +0.5= T VOD=2V &R BRO 1.25 VOD 1.25 : VG 2 ly & NGI & Vpp=av * Consider VGTV (:13 VG L2) 112 Rs 0.51 Power P = VDD - Io → ID = B Io = 5x108 = 2.5 mA. [: un cox = 200 MALVY] : Io = un cox ♡ (VGIS Vrh) ? 2.5X103 = 4 (200x106). W ( 3 – 0.5 -0.5) 2.5 X10-3 = 6.25 X10-6.W → ^ = 2,5X10% = 400 * Vs = Rs. Io → Rs = VS , 025_-= 200-1 + Rs = 2001 ID 2.5x10 * VG = R2 VDD + R2 VG - AU = 0.625 RitR2 RitR2 VDD a * Zin = Rin = RillR2 Rin= R1 R2 = 100KA, RillR2? S sygmugs - Ritra 400 I L 6.25 X 106 1-25 vin G D Vout & Ro Vgs > Rille, :Rinto I i Ri [0,6257 = tická ICA

* 55 = 160 KR Ri(0.625) - 100kn Ri= 100 0.625 R2 = 0.625 R, +0.625 R2 = 0.375 R2 = 0,625 R, R2 = 513 . R1 = (513)(160) = 80013 = 267 kn R1 = 160 K 12, R2 = 267 kn , Rs = 200-12, W = 400 #

Vin * Im = 2 10 = 2(2-5x173 - 20x10 3 ALV - VGS-VH 1.25 -0.5-0.5 Voltage gain Av: Vout = -9m Ro. Vgs (: Vgs = Vin -- Vout = - gm Ro Vîn → Vout = -9mRD lavl = 1 Youtin S = AMRO = 6 + Ro = Some Ro E Roberto 3 = G00 Rp = 60.1 = 300.1 0.3 * Saturation check: Vo = Vpp-ID RD = 2-2.5(35) = 1.25V VD Z VG-VTH = 0,75. condition satisfied