VLSI Basic Circuit Concept MCQ Quiz – Objective Question with Answer for VLSI Basic Circuit Concept

41. What is the total delay of a CMOS pair?

A. 5fƮ
B. 7fƮ
C. 8fƮ
D. 4fƮ

Answer: B

The total delay of a CMOS pair is equal to 7fƮ. This can be calculated by knowing the delay per stage of CMOS.

 

42. The number of stages N can be given as ______

A. ln(y)×ln(f)
B. ln(y)/ln(f)
C. ln(f)/ln(y)
D. ln(f)/ln(2y)

Answer: B

The number of stages N can be given as ln(y)/ln(f). By knowing whether the number of stages N is even or odd we can calculate the total delay for nMOS, CMOS, etc.

 

43. When the number of stages N is even, the total delay for nMOS can be?

A. 1.5NfƮ
B. 2.5NfƮ
C. 3.5NfƮ
D. 4.5NfƮ

Answer: B

When the number of stages N is even, the total delay for nMOS can be given as 2.5NfƮ. This is calculated by using the formula (N/2)×5fƮ.

 

44. 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.

 

45. 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.

 

46. 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.

 

47. 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.

 

48. 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.

 

49. 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.

 

50. 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.

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