Direction: Consider the circuit shown below:
The both transistor have parameter as follows:
VTN = 0.8 V, kn = 30 ΩA/V2
-
If the width-to-length ratios of M1 and M2 are:
W 
= W = 40 L 1 L 2
The output V0 is:
-
- 1.5 V
- 2.5 V
- 5 V
- 0 V
Correct Option: A
For both transistor M1 and M2
VDS = VGS
∴ VDS > VGS – VTN therefore both the transistor are in saturation
ID1 = ID2
ID1 = Kn1 (VGS1 – VTN1 )2
= Kn2 (VGS2 – VTN2)2 …(A)
Kn1 = Kn2 and VTN1 = VTN2
on expanding equation
V2GS1 + V2TN1 – 2VGS1 = V2GS2 + V2TN2 – 2VGS2
or V2GS1 + V2GS2 = 2 (VGS1 – VGS2) …(B)
from given figure,
VGS1 + VGS2 = 5 …(C)
V2GS1 – (5 – VGS1 )2 = 2 (VGS1 – VGS1 + 5)
V2GS1 – 25 – V2GS1 + 10 VGS1 = 10
10 VGS1 = 35
or VGS1 = 3.5
VGS2 = 5 – VGS1 = 5 – 3.5 = 1.5 V
So, V0 = 5 – VGS1 = VGS2 = 1.5 V
