# JNTU B-Tech II Semester Examinations,Vlsi Design, Apr/May 2008

JNTU PAPERS

JNTU B.Tech II Semester Examinations,

Vlsi Design,

, Apr/May 2008

( Common to Electronics & Communication Engineering, Bio-Medical

Engineering and Electronics & Telematics)

Time: 3 hours Max Marks: 80

Answer any FIVE Questions

All Questions carry equal marks

SET-I

1. Describe the two commonly used methods for obtaining integrated capacitor. [16]

2. (a) Explain various regions of CMOS inverter transfer characteristics.

(b) For a CMOS inverter, calculate the shift in the transfer characteristic curve when ?n/?p ratio is varied from 1/1 to 10/1. [8+8]

3. (a) what is a stick diagram? Draw the stick diagram and layout for a CMOS

inverter.

(b) What are the effects of scaling on Vt?

(c) What are design rules? Why is metal- metal spacing larger than poly –poly spacing. [8+4+4]

4. Calculate the rise time and fall time of the CMOS inverter (W/L)n= 6 and (W/L)p=8,

K?

n =150? A/V 2, Vtn =0.7V,K?

p= 62 ? A/V 2, Vtp=-0.85V , VDD =3.3V. Total out-put capacitance =150 fF. [16]

5. (a) Explain the CMOS system design based on the data path operators with a

suitable example.

(b) Draw and explain the basic Memory- chip architecture. [8+8]

6. (a) Draw the typical standard-cell structure showing low-power cell and explain it.

(b) Sketch a diagram for two input XOR using PLA and explain its operation with the help of truth table. [8+8]

7. (a) Write a VHDL Program for a divide-by-3 counter with suitable state diagram.

(b) Compare all available design verification tools. [8+8]

8. (a) Explain how an improved layout can be reduced faults in CMOS circuits.

(b) Explain how a pseudo random sequence generator may be used to test a 16-bit

data path. How would the outputs be collected and checked. [6+10]