project 2 code

clc
clear
close all
vdd = 12;
vt = 1.4;
kn = .0006;
VA = 200;
L = 1/VA;
R1 = 50000;
R2 = 50000;
RS1 = 15000;
RD1 = 15000;
R3 = 50000;
R4 = 50000;
R5 = 100000;
R6 = 400000;
RS2 = 15000;
RD2 = 15000;
RS3 = 20000;
RL = 20000;

syms ID1 VGS1 ID2 ID3 VGS2 VGS3
%%%dc biases
%%first stage
VG1 = vdd*R2/(R1+R2);
ID1 = kn*(VGS1-vt).^2-(VG1-VGS1)/RS1;
VGS1 = solve(ID1,VGS1);
VGS1=max(VGS1)
VS1 = VG1-VGS1
ID1 = kn*(VGS1-vt).^2;
VD1 = vdd-ID1*RD1
%%second stage
VG2 = vdd*R4/(R3+R4);
ID2 = kn*(VGS2-vt).^2-(VG2-VGS2)/RS2;
VGS2 = solve(ID2,VGS2);
VGS2 = max(VGS2);
VS2 = VG2-VGS2;
ID2 = kn*(VGS2-vt).^2;
VD2 = vdd-ID2*RD2;
%%final stage
VG3 = vdd*R6/(R5+R6);
ID3 = kn*(VGS3-vt).^2-(VG3-VGS3)/RS3;
VGS3 = solve(ID3,VGS3);
VGS3 = max(VGS3);
VS3 = VG3-VGS3;
ID3 = kn*(VGS3-vt).^2;
%%VD3=vdd;
VD3 = vdd;

%%%DCLL and ACLL
IDSQ = ID3
VDSQ = VD3-VS3;
%%dcll
%vdd - VDS - IDS(RS3) - IDS(RD3) = 0;
VDS = vdd;
IDS = vdd/(RS3);
%%acll
%vdst +idst(RS3||RL) = VDSQ+IDS(RS3||RL);
vdst = VDSQ +IDS*(RS3^-1+RL^-1)^-1;
idst = (VDSQ +IDS*(RS3^-1+RL^-1)^-1)/((RS3^-1+RL^-1)^-1);

Swing = ((VDSQ-vdst)^2+IDSQ^2)^(1/2)


%%%AC analysis
%other calcs
ro1=1/(L*ID1);
gm1 = 2*kn*(VGS1-vt);
ro2 = 1/(L*ID2);
gm2 = 2*kn*(VGS2-vt);
ro3 = 1/(L*ID3);
gm3 = 2*kn*(VGS3-vt);


%%gain
VIVGS1=1;
VGS2VGS1 = -(ro1^-1+RD1^-1+R3^-1+R4^-1)^-1*gm1;
VG3VGS2 = -(ro2^-1+RD2^-1+R5^-1+R6^-1)^-1*gm2;
VGS3VG3 = 1/(1+gm3*(ro3^-1+RS3^-1+RL^-1)^-1);
VoVGS3 = gm3*(ro3^-1+RS3^-1+RL^-1)^-1
Av = VIVGS1*VGS2VGS1*VG3VGS2*VGS3VG3*VoVGS3