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Microelectronics Question Paper - May 19 - Electronics And Telecomm (Semester 5) - Mumbai University (MU)

## Microelectronics - May 19

### Electronics And Telecomm (Semester 5)

Total marks: 80
Total time: 3 Hours
INSTRUCTIONS
(1) Question 1 is compulsory.
(2) Attempt any three from the remaining questions.
(3) Draw neat diagrams wherever necessary.

1.a. Compare constant voltage scaling and full voltage scaling.
(5 marks) 13158

1.b. Compare single ended and differential power amplifiers.
(5 marks) 00

1.c. Why folded cascode is very popular building block in CMOS amplifier? Explain its advantages over double cascade.
(5 marks) 13143

1.d. Derive output resistance of MOS current source.
(5 marks) 00

(5 marks) 00

2.a. Design an NMOS current source to provide a bias current of $I_{Q}=100 \mu A$ and an output resistance greater than 20 $\mathrm{M} \Omega$ . The reference current is to be $I_{\text {ref}}=150 \mu A$ . The circuit is to be biased at $\pm 3.3 \mathrm{V}$ and the voltage at the drain of the current source transistor is to be no smaller than $-2.2 \mathrm{V}$ . The minimum width to length ratio of transistor is to be unity.
(12 marks) 00

2.b. Explain cascode current mirror in detail.
(8 marks) 13146

3.a. For CS amplifier with current source load find intrinsic gain $A_o$ and explain the effect of output resistance on gain.
(10 marks) 13139

3.b. For CS stage with resistive load amplifier prove that Gain $=-g_{m} r_{d}$
(6 marks) 00

(4 marks) 13142

4.a. Explain PMOS fabrication process with suitable diagrams.
(10 marks) 13156

4.b. Explain with proper diagram CLASS F power amplifier.
(10 marks) 13124

5.a. Explain in detail fabrication of transformer.
(10 marks) 13126

5.b. Explain short channel effects in MOSFET.
(10 marks) 13159

6.a. Explain DC transfer characteristics of MOS differential amplifier.
(10 marks) 13132

6.b. Calculate the DC characteristics of MOSFET differential amplifier shown in Fig .6$(b)$ the transistor parameters are $k_{n 1}=k_{n 2}=0.1 \frac{\mathrm{mA}}{\mathrm{v}^{2}}, k_{n 3}=k_{n 4}=0.3 \frac{\mathrm{m} A}{\mathrm{v}^{2}},$ and for all transistor $\lambda=0$ and $V_{\mathrm{tn}}=1 \mathrm{V}$ . Determine the maximum range of common-mode input voltage.
(10 marks) 00

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