# MOSFET Amplifier with CD Configuration – 1 MCQ’s

This set of Analog Electronic Circuits Multiple Choice Questions & Answers (MCQs) focuses on “MOSFET Amplifier with CD Configuration – 1″.

1. If channel length modulation is present, what is the voltage gain?

a) ro1 / {(1/gm1 || ro2) + ro1}
b) ro2 / (1/gm1 + ro1)
c) ro2 / (1/gm1 + 3ro2)
d) ro2 / (2/gm1 + ro2)

2. The output impedance of the follower is _____________
a) Low
b) Very low
c) Depends on it’s transconductance and low
d) High

3. If channel length modulation is present, what is the impedance looking into node X?

a) (1/gm2 || ro2 || 1/gm1)
b) (1/gm2 || 1/gm1 || ro1)
c) (1/gm2 || ro2 || 12/gm1 || ro1)
d) (1/gm2 || ro2 || 1/gm1 || ro1)

4. If channel length modulation is present in M1 but not in M2, what is the voltage gain at node X?

a) (1/gm2 || ro2) / {1/gm2 + ( 1/gm1 || ro1)}
b) (1/gm1 || ro1) / (1/gm2 + ro1)
c) 1/gm1 / (1/gm2 + 1/gm1)
d) 1/gm1 / {1/gm2 + (1/gm1 || ro1)}

5. The follower stage provides _____ input impedance.
a) low
b) equal
c) very high
d) very low

6. The follower stage is mostly used as a ____________
a) Current source
b) Buffer stage
c) Amplifier
d) Switch

7. Neglecting Channel Length Modulation, if the transconductance increases, the input impedance of a follower stage ___________
a) Remans the same
b) Increases
c) Decreases
d) Doubles

8. Assume µnCox = 100 µA/V2 and supply current is 5mA, what should be the aspect ratio so that a 50 Ω load can be used to give a voltage gain of .25 in C.D. configuration?
a) 32.6
b) 50
c) 40
d) 41

9. If maximum power is transferred to the load R1, the transconductance is .02 and channel length modulation is neglected, what should be the value of the load?

a) 50 Ω
b) 32 Ω
c) 16 Ω
d) 10 Ω

10. Neglecting Channel Length Modulation, if the aspect ratio of the MOSFET increases, the gain of the follower stage will _________
a) increase
b) decrease
c) increases proportionately
d) doesn’t get affected

11. If g is the transconductance and r is the resistance due to channel length modulation – what is the total voltage gain if only M1 has channel length modulation?

a) R / ((1/g || r ) + R) * g *R * R / (1/g + R)
b) R / ((1/g || r ) + R) * g *R * R * g
c) R / ((1/g || r )) * g *R * R / (1/g + R)
d) R / ((1/g ) + R) * g *R * R / (1/g + R)

12. If g is the transconductance and r is the resistance due to channel length modulation – what is the total voltage gain if both M2 and M3 has channel length modulation?

a) R/ ((1/g || r) + R) * g * (R || r) * R * g
b) R/ ((1/g + R) * g * (R || r) * R/ ((1/g || r) + R)
c) R/ ((1/g || r)) * g *R * R/ ((1/g || r) + R)
d) R/ ((1/g ) + R) * g *R * R *2g

13. Neglecting Channel Length Modulation, if the transconductance of a MOSFET increases, the output impedance of the follower stage can _________
a) increase
b) decrease
c) increase linearly
d) decrease non-linearly

14. If g is the transconductance and r is the resistance due to channel length modulation – what is the total voltage gain if both M1 and M3 has channel length modulation?

a) R / ((1/g || r) + R) * g * R * R / ((1/gm || r))
b) R / ((1/g + 4R) * g * R / ((1/g || r) + 3R)
c) R / ((1/g || r)) * g *R * R / ((1/g || r) + 2R)
d) R / ((1/g) * R * R * g * 4g

15. Neglecting Channel Length Modulation, if the transconductance of the MOSFET increases, the gain of the follower stage will _________
a) decreases
b) increases
c) doesn’t get affected
d) doubles