# VLSI Questions and Answers – MOS Circuits Area Capacitance and Delay Unit

This set of VLSI Multiple Choice Questions & Answers (MCQs) focuses on “MOS Circuits Area Capacitance and Delay Unit”.

1. Which of the following mainly constitutes the output node capacitance?
a) Inter electrode capacitance
b) Stray capacitance
c) Junction Parasitic capacitance
d) All of the mentioned
View Answer

Answer: c
Explanation: Output node capacitance mainly consists of junction parasitic capacitance.
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2. The junction parasitic capacitance are produced due to ____________
a) Source diffusion regions
b) Gate diffusion regions
c) Drain diffusion region
d) All of the mentioned
View Answer

Answer: c
Explanation: The junction parasitic capacitance are produced due to drain diffusion capacitance.

3. The amount of parasitic capacitance at the output node is determined by __________
a) Concentration of the impurity doped
b) Size of the total drain diffusion area
c) Charges stored in the capacitor
d) None of the mentioned
View Answer

Answer: b
Explanation: The amount of parasitic capacitance is a linear function of drain diffusion area.

4. The dominant component of the total output capacitance in submicron technology is?
a) Drain diffusion capacitance
b) Gate oxide capacitance
c) Interconnect capacitance
d) Junction parasitic capacitance
View Answer

Answer: c
Explanation: Interconnect capacitance becomes dominant component in submicron technology.

5. Which of the following is dominant component in input capacitance?
a) Gate diffusion capacitance
b) Gate parasitic capacitance
c) Gate oxide capacitance
d) All of the mentioned
View Answer

Answer: c
Explanation: For input capacitance, gate oxide capacitance is the main component.
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6. The total load capacitance is calculated as the sum of __________
a) Drain capacitance in series with input capacitance
b) Drain capacitance + interconnect capacitance +input capacitance
c) Drain capacitance + interconnect capacitance – input capacitance
d) Drain capacitance in parallel with input capacitance
View Answer

Answer: b
Explanation: Total load capacitance = Drain capacitance + interconnect capacitance +input capacitance.

7. The interconnect capacitance is formed by __________
a) Area between the interconnect lines
b) Interconnect lines between the gates
c) Inter electrode capacitance of interconnect lines
d) None of the mentioned
View Answer

Answer: b
Explanation: Interconnect line between the gates form interconnect capacitance.

8. The amount of gate oxide capacitance is determined by __________
a) Charges present on the gate
b) Polarity of the gate
c) Charges present on the substrate
d) Area of the gate
View Answer

Answer: d
Explanation: The amount of gate oxide capacitance is determined by the area of the gate.

9. By what amount is Sidewall doping larger than substrate doping concentration.
a) 5
b) 2
c) 1
d) 10
View Answer

Answer: d
Explanation: The sidewall doping is 10 times larger.
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10. Zero bias depletion capacitance per unit length at sidewall junctions is given by, (Cj is the zero bias depletion capacitance per unit area).
a) (√10).Cj.xj
b) (√5).Cj.xj
c) (√10).Cj.xj2
d) (√10).Cj.xj3
View Answer

Answer: a
Explanation: Since the doping concentration is 10 times larger.

11. The typical value of capacitance in pF x 10-4/µm2 for gate to channel in λ based design is?
a) 1
b) 0.4
c) 0.2
d) 4
View Answer

Answer: d
Explanation: The gate to channel capacitance in λ based design is 4 pF x 10-4/µm2.

12. The active capacitance is also called as __________
a) Parasitic capacitance
b) Interconnect capacitance
c) Junction capacitance
d) Diffusion capacitance
View Answer

Answer: d
Explanation: Diffusion capacitance is also called as active capacitance.

13. The value of diffusion capacitance in pF x 10-4/µm2 in 2 µm design is?
a) 1.75
b) 4
c) 8
d) 16
View Answer

Answer: c
Explanation: Diffusion capacitance has a value of 8 pF x 10-4/µm2.
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14. The value of standard unit of capacitance is?
a) 0.01pF
b) 0.0032pF
c) 0.0023pF
d) All of the mentioned
View Answer

Answer: d
Explanation: The value of standard unit of capacitance depends on the design style used.

15. The standard unit of capacitance is defined as?
a) Capacitance of gate to channel of MOS transistor having W = L dimensions
b) Capacitance of gate to channel of n-MOS transistor having W = 3L dimensions
c) Capacitance of gate to channel of p-MOS transistor having 3W = L dimensions
d) Capacitance of gate to channel of n-MOS transistor having W = L dimensions and p-MOS having W=3L dimensions
View Answer

Answer: a
Explanation: Standard capacitance is capacitance of gate to channel with standard area.

Sanfoundry Global Education & Learning Series – VLSI.

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advertisement Manish Bhojasia, a technology veteran with 20+ years @ Cisco & Wipro, is Founder and CTO at Sanfoundry. He is Linux Kernel Developer & SAN Architect and is passionate about competency developments in these areas. He lives in Bangalore and delivers focused training sessions to IT professionals in Linux Kernel, Linux Debugging, Linux Device Drivers, Linux Networking, Linux Storage, Advanced C Programming, SAN Storage Technologies, SCSI Internals & Storage Protocols such as iSCSI & Fiber Channel. Stay connected with him @ LinkedIn | Instagram | Facebook | Twitter