//Example 1.25 clc disp("Step 1: Identify topology") disp("By making Vo = 0, feedback current becomes zero. Hence it is a voltage sampling. The feedback is fed in shunt with the input signal and thus the topology is voltage shunt feedback") disp("") disp("Step 2 and Step 3: Find input and output circuit") disp("To find input circuit, set Vo = 0. This places resistor R across the input. To find output circuit, set V_i = 0. This places resistor R across output. The resultant circuit is shown in fig 1.72") disp("") disp("Step 4: Replace FET with its equivalent circuit as shown in fig 1.73") disp("") disp("Step 5 : Find open loop transresistance") disp("R_M = Vo/I_s = -g_m*V_gs*R_eff/I_s") reff=(40*200*10)/((200*10)+(400)+(40*200)) format(5) disp(reff,"where R_eff(in k-ohm) = r_d || R || R_D =") disp("and V_gs = I_s*R_i = I_s * R_s||1M||R") disp(" = I_s * 10K||1M||200K") disp(" = 9.43*10^3 I_s") rm=-2.5*9.43*7.69 format(7) disp(rm,"R_M(in k-ohm) =") disp("") disp("Step 6: Calculate beta") b=-1/(200*10^3) format(7) disp("beta = I_f/Io = V_i-Vo/Vo*R =") disp(b," = -1/R = because (Vo > V_i)") disp("") disp("Step 7: Calculate D, R_Mf, A_vf, R_of, R''_of") d=1+(5*181.29*10^-3) format(4) disp(d,"D = 1 + beta*R_M =") rmf=-181.29/1.9 format(7) disp(rmf,"R_Mf(in k-ohm) = R_M/D =") avf=-95.415/10 format(7) disp(avf,"A_vf = V0/V_s = Vo/I_s*R_s = R_Mf/R_s =") ri=(10*1000*200)/((1000*200)+(10*200)+(1000*10)) format(5) disp(ri,"R_i(in k-ohm) = R_s || M || R =") rif=(9.43)/1.9 format(6) disp(rif,"R_if(in k-ohm) = R_i/D =") ro=(40*200*10)/((200*10)+(400)+(40*200)) format(5) disp(ro,"R''_o(in k-ohm) = r_eff = r_d || R || R_D =") rof=(7.69/1.9) format(2) disp(rof,"R''_of(in k-ohm) = R''_o/D =")