Capacitive Loads and Wiring Capacitances

Question 1
Marks : +2 | -2
Pass Ratio : 100%
The capacitances in MOSFET occurs due to _____________
Interconnects
Difference in Doping concentration
Difference in dopant materials
All of the mentioned
Explanation:
The on-chip capacitances found in MOS circuits are due to interconnects, difference in Doping concentration, difference in dopant materials.
Question 2
Marks : +2 | -2
Pass Ratio : 100%
In cut-off mode, the value of gate to substrate capacitance is equal to ___________
Cox .(W- L)
Cox W/ L
Cox* W*L
0
Explanation:
In Cut-off mode, the conducting channel does not exist, so gate-to-source and the gate-to-drain capacitances are both equal to zero. Therefore, the gate to substrate capacitance is equal to Cox* W*L.
Question 3
Marks : +2 | -2
Pass Ratio : 100%
In saturation mode operation, gate to drain capacitance is zero due to ___________
Gate and drain are interconnected
Channel length is reduced
Inversion layer doesn’t exist
Drain is connected to ground
Explanation:
Due to the pinched off channel, the capacitance between source to drain is reduced to zero.
Question 4
Marks : +2 | -2
Pass Ratio : 100%
The proper DC model of MOSFET with capacitances is?
None of the mentioned
Explanation:
The capacitances exist between all the regions of the MOSFET.
Question 5
Marks : +2 | -2
Pass Ratio : 100%
In Cut-off Mode, the capacitance Cgs will be equal to ___________
2Cgd
0
Cgb
All of the mentioned
Explanation:
In cut-off mode, the conducting channel does not exist, so gate-to-source and the gate-to-drain capacitances are both equal to zero.
Question 6
Marks : +2 | -2
Pass Ratio : 100%
The capacitance that exist between Gate and Bulk is called as ___________
Oxide parasitic capacitance
Metal oxide capacitance
MOS capacitance
None of the mentioned
Explanation:
The capacitance that exist between Gate and Bulk is called as an oxide parasitic capacitance.
Question 7
Marks : +2 | -2
Pass Ratio : 100%
When MOSFET is operating in saturation region, the gate to source capacitance is?
1/2*Cox*W*L
2/3*Cox*W*L
Cox*W*L
1/3*Cox*W*L
Explanation:
Due to the reduction in channel length, gate to drain and gate to substrate capacitance are zero, the gate to channel capacitance as seen between the gate and the source is approximately defined as 2/3*Cox*W*L.
Question 8
Marks : +2 | -2
Pass Ratio : 100%
The parasitic capacitances found in MOSFET are ___________
Oxide related capacitances
Inter electrode capacitance
Electrolytic capacitance
All of the mentioned
Explanation:
The parasitic device capacitances can be classified into two major groups: oxide-related
Question 9
Marks : +2 | -2
Pass Ratio : 100%
In the below graph, the regions marked as A,B,C are?
A : Saturation, B : Linear, C : Cut-off
A :Cut-off, B : Linear, C : Saturation
A : Linear, B : Saturation, C : Cut-off
None of the mentioned
Explanation:
The gate to substrate capacitance exists only in cut-off region, and gate to drain capacitance exist only in saturation region.
Question 10
Marks : +2 | -2
Pass Ratio : 100%
In linear mode operation, the parasitic capacitances that exists are ___________
Nonzero Gate to source capacitance
Nonzero Gate to drain capacitance
Zero gate to substrate capacitance
All of the mentioned
Explanation:
In linear-mode operation, the conducting channel exists, therefore there will be a finite amount of gate to source and gate to drain capacitances. Since the conducting channel exists, gate to substrate capacitance is reduced to zero.