VLSI Inverter Delay MCQ Quiz – Objective Question with Answer for VLSI Inverter Delay

21. When the number of stages N is even, the total delay for CMOS can be?
A. 1.5NfƮ
B. 2.5NfƮ
C. 3.5NfƮ
D. 4.5NfƮ

Answer: C

When the number of stages N is even, the total delay for CMOS can be given as 3.5NfƮ. This is calculated by using the formula (N/2)*7fƮ.

 

22. In BiCMOS drivers, the input voltage Vbe is _______ on base width.

A. directly proportional
B. inversely proportional
C. logarithmically proportional
D. exponentially proportional

Answer: C

In the BiCMOS driver, the input voltage Vbe is logarithmically proportional to the base width Wb and on electron mobility.

 

23. Which has a larger value?

A. Tin
B. TL
C. Rc
D. None of the mentioned

Answer: A

In BiCMOS drivers, the initial time Tin necessary to charge the base-emitter junction is larger than the time TL requires to charge the output load capacitance.

 

24. In BiCMOS driver, a good bipolar transistor should have ___________

A. low Rc
B. high hfe
C. high gm
D. all of the mentioned

Answer: D

In BiCMOS drivers, a good bipolar transistor should have low Rc, high hfe, high gm, etc.

 

25. Propagation time is directly proportional to ____________

a) x
b) 1/x
c) x2
d) 1/x2

Answer: c

The propagation time is directly proportional to the square of the Propagation distance (x2). It is the time taken by the signal to move from the input port to the output port.

 

26. The total resistance can be given as ___________

a) nRs
b) nrRs
c) rRs
d) Rs

Answer: b

The total resistance can be given as the product of nrRs where r is the relative resistance per section in terms of Rs.

 

27. Total capacitance can be given as ___________

a) n(square Cg)
b) nc(square Cg)
c) c(square Cg)
d) square Cg

Answer: b

Total capacitance can be given as the product of nc(square Cg) where c is the relative capacitance per section in terms of square Cg.

 

28. Overall delay is directly proportional to _______

a) n
b) 1/n
c) n2
d) 1/n2

Answer: c

The overall delay is directly proportional to n2, where n is the number of pass transistors in series.

 

29. The number of pass transistors connected in series can be increased if _______

a) compressor is connected
b) buffer is connected
c) ground is connected
d) voltage regulator is connected

Answer: b

The number of pass transistors connected in series can be increased by connecting buffer in between.

 

30. Buffer is used because ___________

a) it increases the speed
b) decreases sensitivity to noise
c) decreases speed
d) does not affect speed

Answer: a

Buffer is used for long polysilicon runs because it increases the speed and reduces the sensitivity to noise.

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