1
GATE ECE 2021
Numerical
+1
-0

An asymmetrical periodic pulse train $v_{\text {in }}$ of 10 V amplitude with on-time $T_{\mathrm{ON}}=1 \mu \mathrm{~s}$ is applied to the circuit shown in the figure. The diode $D_1$ is ideal.

GATE ECE 2021 Analog Circuits - Diodes Question 2 EnglishThe difference between the maximum voltage and minimum voltage of the output waveform $v_0$ (in integer) is $\_\_\_\_$ V.

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2
GATE ECE 2021
MCQ (Single Correct Answer)
+1
-0.33

In the circuit shown in the figure, the transistors $M_1$ and $M_2$ are operating in saturation. The channel length

modulation coefficients of both the transistors are non-zero. The transconductance of the MOSFETs $M_1$ and $M_2$ are $g_{m 1}$ and $g_{m 2}$, respectively, and the internal resistance of the MOSFETs $M_1$ and $M_2$ are $r_{01}$ and $r_{02}$ respectively.

GATE ECE 2021 Analog Circuits - FET and MOSFET Question 4 EnglishIgnoring the body effect, the ac small signal voltage gain ( $d V_{\text {out }} / d V_{\text {in }}$ ) of the circuit is

A

$-g_{m 2}\left(r_{01} \amalg r_{02}\right)$

B

$-g_{m 2}\left(\frac{1}{g_{m 1}} \| r_{02}\right)$

C

$-g_{m 1}\left(\frac{1}{g_{m 2}}\left\|r_{01}\right\| r_{02}\right)$

D

$-g_{m 2}\left(\frac{1}{g_{m 1}}\left\|r_{01}\right\| r_{02}\right)$

3
GATE ECE 2021
Numerical
+1
-0

A circuit with an ideal OPAMP is shown in the figure. A plus $V_{\text {IN }}$ of 20 ms duration is applied to the input. The capacitors are initially uncharged.

GATE ECE 2021 Analog Circuits - Operational Amplifier Question 8 English The output voltage $V_{\text {OUT }}$ of this circuit at $\tau=0^{+}$(in integer) is $\_\_\_\_$ V.
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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

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