Solution 4 :

(a)

The value of KL = K' (W / L)L = 20 * (10 / 5) = 40 * 10^-6 A / V^2

The value of KO = K' (W / L)O = 20 * (20 / 5) = 80 * 10^-6 A / V^2

(b)

The output high voltage,

VOH = VDD = 5v

The input low voltage,

VIL = VT,O + [KL / (KO * KL + KO^2)^0.5] * mag(VT,L)

= 1 + [40 / (40 * 40 + 80^2)^0.5] * mag(-3)

= 2.22v

The input high voltage,

VIH = VT,O + 2 * mag(VT,L) * (KL / 3KO)^0.5

= 1 + 2 * 3 (40 / (3 * 80)^0.5

= 3.45V

The output low voltage,

VOL = KL (VT,L)^2 / 2 * KO(VDD - VT,O)

= 40 * 9 / 2 * 80(5 - 1)

= 0.56v

The midpoint voltage,

VM = VT,O + VT,L (KL / KO)^0.5

= 1 + 3 (40 / 80)^0.5

= 3.12v

Noise margins :

Noise margin low,

VNML = VIL - VOL = 2.22 - 0.56 = 1.66v

Noise margin high,

VNMH = VOH - VIH = 5 - 3.45 = 1.55v