This set of VLSI Multiple Choice Questions & Answers (MCQs) focuses on “System Considerations”.
1. Clock line drivers has ____ source of drive
Explanation: Clock line drivers has one source of drive. The speed of bipolar drivers is not fully realized with bus lines.
2. Bus structures carry
a) data signals
b) control signals
c) data and control signals
d) in and out signals
Explanation: Bus structures carry both data and control signals. They are generally long and connected to and through a significant number of circuits and subsystems.
3. Bus has ___ different classes
Explanation: Bus has three different classes and those are passive, active and precharged.
4. In passive bus, drivers are connected through
a) series switches
b) parallel switches
c) cascade switches
Explanation: In passive bus, drivers are connected through series switches. It is a floating rail to which signals may be connected from drivers through series switches.
5. The bus rail in active bus has
a) NAND connection
b) AND connection
c) NOR connection
d) OR connection
Explanation: The bus rail in active bus has NOR connection which has a common pull up and ntype pull down transistors.
6. Low L:W ratio results in ____ transistors
c) size doesnt depend on ratio
d) less effective
Explanation: The size of the transistor can be made large by small L:W ratio and thus it has a low resistance.
7. Features which does not affect bus design are
b) delay factors
c) non delay factors
d) cross talk and delay factors
Explanation: Cross-talk and delay factors are of significance in bus design. This occurs when many signals on chip is propogated.
8. Which device is frequency dependent?
Explanation: CMOS is frequency dependent where as BiCMOS is not and it exhibits constant value for power dissipation.
9. If the current density exceeds a threshold value then metal atoms moves in
a) direction of the current
b) opposite direction of the current
c) doesnt depend on direction of current
d) direction of the voltage
Explanation: If the current density exceeds a threshold value then metal atoms starts to move in the direction of current.
10. At narrowing or constriction point current density is
c) remains low after going to high point
d) becomes high from low
Explanation: At narrowing or constriction point, current density is at its highest. At these points metal is transported from the constricted regions become even more constricted and eventually may blow like a fuse.
11. During relaxation effect, electron flow occurs in
a) short pulses
b) at steady state level
c) large pulses
d) very large pulses
Explanation: During relaxation effect, electron flow occurs in short pulses rather than at steady state level.
12. Line impedance is given by
Explanation: The line impedance Zo is given by (L/C)^1/2 where L and C are values per unit length of the bus.
13. IR drops brings ______ in noise margin
c) does not affect
Explanation: IR drops bring about deterioration in noise margins. Transient voltages induced in either Vdd or Vss rail may lead to noise margin problems.
Sanfoundry Global Education & Learning Series – VLSI.
To practice all areas of VLSI, here is complete set of 1000+ Multiple Choice Questions and Answers.