Transconductance MCQ Quiz in తెలుగు - Objective Question with Answer for Transconductance - ముఫ్త్ [PDF] డౌన్లోడ్ కరెన్
Last updated on Apr 22, 2025
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Transconductance Question 1:
Two n-channel MOSFETs, T1 and T2, are identical in all respects except that the width of T2 is double that of T1. Both the transistors are biased in the saturation region of operation, but the gate overdrive voltage (VGS - VTH) of T2 is double that of T1, where VGS and VTH are the gate-to-source voltage and threshold voltage of the transistors, respectively. If the drain current and transconductance of T1 are ID1 and gm1 respectively, the corresponding values of these two parameters for T2 are
Answer (Detailed Solution Below)
Transconductance Question 1 Detailed Solution
Concept:
n-channel MOSFET biased in saturation region will result in a current given by:
And the transconductance is defined as
Calculation:
Given, two transistors T1 and T2 which are identical in all respects except for width and gate overdrive voltage (VGS - Vth).
For T1 MOSFET,
gm1 ∝ W1 (VGS - Vth)1 and ID1 ∝ W1 (VGS - Vth)21
Similarly for T2, gm2 ∝ W2 (VGS - Vth)2 and ID2 ∝ W2 (VGS - Vth)22
Given W2 = 2W1,
And (VGS - Vth)2 = 2 (VGS - Vth)1
Putting these in Equation (1), we get,
Similarly,
gm2 = 4gm
Transconductance Question 2:
The small signal voltage gain of the common-source Amplifier shown in the figure if
Answer (Detailed Solution Below) -4 - -3
Transconductance Question 2 Detailed Solution
Concept:
Voltage gain is given by:
Av = - gmRD
Calculation:
AV = - gmRD
= -3.33
Transconductance Question 3:
The small signal output resistance R0 of the NMOS circuit if ID = 0.5 mA, λ = 0.02 V-1,
Answer (Detailed Solution Below) 2.1 - 2.3
Transconductance Question 3 Detailed Solution
The small signal model with a test voltage Vx is shown.
The output resistance is given by
From the circuit
Vgs = Vx
Applying KCL
Calculation of gm
= 0.447 mA/V
= 2.19 k
Transconductance Question 4:
The table shows the standard values of NMOS transistor using 0.25 μm technology.
|
Parameter |
Value |
|
tox (nm) |
6 |
|
Cox (bF/μm2) |
5.8 |
|
μ (cm2/V-sec) |
460 |
|
μ - Cox (μA/V2) |
267 |
|
Vto (V) |
0.5 |
|
VDD (V) |
2.5 |
|
VA’|(V/μm) |
5 |
|
C0V (bF/μm) |
0.3 |
If NMOS is operating at 100 μA of drawn current and L = 0.4 um W = 4 um. The intrinsic gain of the NMOS is
Answer (Detailed Solution Below)
Transconductance Question 4 Detailed Solution
For NMOS:
= 0.73 mA/V
A0 = gm r0 = 0.73 × 20
= 14.6 V/V
Transconductance Question 5:
Consider the CMOS common-source amplifier shown in the figure. If VDD = 3V, Vtn = |Vtp| = 0.6 V,
Answer (Detailed Solution Below)
Transconductance Question 5 Detailed Solution
The circuit shown is CMOS circuit implementation of the common-source amplifier.
Here load = Q2 transistor and output is taken across Q1
Av = -gm1 (r01||r02)
= - 0.63 (mA/V) × (200||100) kΩ
= -42 V/V
Transconductance Question 6:
A enhancement type N-Channel MOSFET is biased in linear region and is used as voltage controlled resistor. If the drain-source resistance is 500Ω for VGS = 2V then the drain-source resistance at VGS = 5 V is _________ Ω
Take VT = 0.5 V
Answer (Detailed Solution Below) 166 - 167
Transconductance Question 6 Detailed Solution
In linear region MOSFET drain current
In linear region with very small VDS the equation can be written as
VDS = 500 Ω for VGS = 2V
When VGS = 5V