example 7.4 page 700
generic differential amp, I=0.8mA
given W/L = 100, uCox = 0.2mA/VV, Va=20V, Rd=5K
find Vov, gm, Ro, Ad
Vov:
Id = uCox/2 * W/L * VovVov
at DC, Id1=Id2=0.4mA
0.4m = 0.2m*100*VovVov => Vov = 0.2V

gm = uCoxWVov/L = 4mA/V

Ro = Va/Id = 20/0.4m = 50K ohms

Ad = gmRd = 18.2V/V

example 7.5 page 702
differential fet amp
given W/L=100
q1,q2 matched
Rd=5k

find Ad, Acm, CMRR in dB, single ended ouput

gm (small sig) = sqrt(2uCoxWId/L)
Id = I/2 at DC bias point for amp
gm = sqrt(stuff) = 4mA/V
Ad = gmRo/2 = 10V/V
Acm = Rd/2Rss = 0.1V/V
CMRR = 20log(Ad/Acm) = 40dB

for single ended:
Ad = gmRo = 20V/V
Acm = 0 for differential output
CMRR = inf

1% change in Rd
Ad = gmRd = 10V/V
Acm = -Rd/2Rss * delRd/Rd = -1/10 * 1/100 ~~ -1mV/V
CMRR = 20log(20/0.001) = 86dB

watch for current mirrors, diff amps, miller capacitance, true/false on midterm