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For the amplifier shown in following figure, determine-
1. Gm, rd
2. Zi, Zo, Av values in each case for both with and without rd.
1 Answer
written 3.0 years ago by |
Step 1 :
Calculate $r_d$ -
$r_d=\dfrac{1}{Y_{os}}$
$\therefore r_d=\dfrac{1}{20 \times 10^{-6}}$
$\therefore r_d=50k \Omega$
Step 2 :
Calculate $g_m$
$\therefore g_m=\dfrac{I_D}{V_{DSQ}}$
But $I_D=\dfrac{V_{DD}-V_{DSQ}}{R_D}$
$\therefore I_D=\dfrac{10-2.75}{3.3}=2.197mA$
$\therefore g_m=\dfrac{2.197}{2.75}=0.7989mS$
Analysis with $r_d$
Step 1 :
Calculate $A_V$
$\therefore A_V=\dfrac{V_0}{V_i}=\dfrac{-g_mV_{gs}(r_d\mid\mid R_D \mid\mid R_F)}{V_gs}=-g_m(r_d\mid\mid R_D \mid\mid R_F)$
$\therefore A_V=-0.7989 \times 10^{-3}[50k \mid\mid3.3k\mid\mid10M]$
$\therefore A_V=-0.7989 …