1
GATE ECE 2024
Numerical
+2
-0

An NMOS transistor operating in the linear region has $I_{D}$ of 5 $\mu$A at $V_{DS}$ of 0.1 V. Keeping $V_{GS}$ constant, the $V_{DS}$ is increased to 1.5 V.

Given that $\mu_{n}C_{ox} \frac{W}{L}$ = 50 $\mu$A/$V^2$, the transconductance at the new operating point (in $\mu$A/V, rounded off to two decimal places) is ______.

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2
GATE ECE 2022
MCQ (Single Correct Answer)
+2
-0.67

Consider an ideal long channel nMOSFET (enhancement-mode) with gate length 10 $$\mu$$m and width 100 $$\mu$$m. The product of electron mobility ($$\mu$$n) and oxide capacitance per unit area (Cox) is $$\mu$$nCox = 1 mA/V2. The threshold voltage of the transistor is 1 V. For a gate-to-source voltage VGS = [2 $$-$$ sin(2t)] V and drain-to source voltage VDS = 1 V (substrate connected to the source), the maximum value of the drain-to-source current is ___________.

A
40 mA
B
20 mA
C
15 mA
D
5 mA
3
GATE ECE 2022
Numerical
+2
-0

Consider the circuit shown with an ideal long channel nMOSFET (enhancement mode, substrate is connected to the source). The transistor is appropriately biased in the saturation region with VGG and VDD such that it acts as a linear amplifier. vi is the small-signal ac input voltage. vA and vB represent the small-signal voltages at the nodes A and B, respectively. The value of $${{{v_A}} \over {{v_B}}}$$ is __________ (rounded off to one decimal place).

GATE ECE 2022 Analog Circuits - FET and MOSFET Question 14 English

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4
GATE ECE 2021
MCQ (Single Correct Answer)
+2
-0.67

For an $n$-channel silicon MOSFET with 10 nm gate oxide thickness, the substrate sensitivity ( $\partial V_T / \partial\left|V_{B S}\right|$ ) is found to be $50 \mathrm{mV} / \mathrm{V}$ at a substrate voltage $\left|V_{B S}\right|=2 \mathrm{~V}$, where $V_T$ is the threshold voltage of the MOSFET. Assume that, $\left|V_{B S}\right| \gg 2 \phi_B$, where $q \phi_B$ is the separation between the Femi energy level $E_F$ and the intrinsic level $E_i$ in the bulk. Parameters given are

Electron charge $(q)=1.6 \times 10^{-9} \mathrm{C}$

Vacuum permittivity $\left(\varepsilon_o\right)=8.85 \times 10^{-12} \mathrm{~F} / \mathrm{m}$

Relative permittivity of silicon $\left(\varepsilon_{S i}\right)=12$

Relative permittivity of oxide $\left(\varepsilon_{o x}\right)=4$

The doping concentration of the substrate is

A

$2.37 \times 10^{15} \mathrm{~cm}^{-3}$

B

$4.37 \times 10^{15} \mathrm{~cm}^{-3}$

C

$9.37 \times 10^{15} \mathrm{~cm}^{-3}$

D

$7.37 \times 10^{15} \mathrm{~cm}^{-3}$

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