# GTU Integrated Circuits and Applications Question Paper June 2012

GUJARAT TECHNOLOGICAL UNIVERSITY

BE- Vth SEMESTER-EXAMINATION – MAY/JUNE – 2012

Subject code: 151003

Subject Name: Integrated Circuits and Applications

Total Marks: 70

Instructions:

1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.

Q.1 (a) Explain all the three open loop Op-Amp configurations.

(b) Consider the Sallen Key low pass circuit for gain K=1, which is to be designed to realize a pair of

poles at the angles ±¥ with respect to negative real axis of S plane. If R1=R2    =1, show that Cosy =

(c) Draw the high frequency model of an Op-Amp and Obtain the expression for the open loop gain as a function of frequency.

Q.2 (a) Define slew rate of an Op-Amp .What are its causes?

(b) Derive the expression for the closed loop voltage gain, input resistance and output resistance of voltage series feedback amplifier.

OR

Q.2 (a) Implement an integrator using Op-Amp. Obtain the expression for the output voltage V0.Sketch the output waveform for an input square waveform. Show the frequency response of an ideal and a practical integrators

(b) Define the following parameters of Op-Amp:

(i)                 Input bias current

(ii)               Common Mode Rejection ratio

(iii)              Supply Voltage rejection ratio.

(iv)              Output offset voltage

Q.3 (a) Explain the working of a Voltage to Current converter with floating load.

Illustrate the application of this circuit as a Zener diode tester.

(b)        Show how Op-Amp can be used as an averaging,summing amplifiers using  noninverting configuration.

(c)        State the properties of Butterworth filter

OR

Q.3 (a) Explain the application of Op-Amp as :

(i) Peaking Amplifier (ii) Schmitt Trigger

(b) Explain the operating principle of a Phase Locked Loop.

Q.4 (a) Explain with a neat circuit diagram and waveforms,the operation of a monostable multivibrator using 555 timer .

(b) Determine the following for the low pass specifications below: amax=0.5 dB,amin= 30 dB.rop=1000 rad/s,®s=2330 rad/s.

(a)    The order of the filter ‘n’

(b)   S plane location of the poles

(c)    Q of each pole.

(d)   00

( c) Name the different types of voltage regulators

OR

Q.4 (a) Draw the circuit diagram of triangular waveform generator and explain the operation with necessary equations and waveforms.

(b) Show how four Op-Amp Biquad circuit can be used as a universal filter. Derive the expression for the transfer function, and plot the magnitude response,pole-zero locations for all types of filter.

Q.5 (a) Draw and explain the block diagrams of (i) Operational amplifier (ii) 555  timer

(b) For an astable multivibrator using 555 Timer, Ra=4.7KQ, Re=1KQ,and  C=.05|iF,determine the positive pulse width, negative pulse width and the free running frequency.

Q.5 (a) Using LM 317, design an adjustable voltage regulator to satisfy the

specifications :V0=10 to 15 volts,I0=0.5A,Choose R1=200Q.Neglect IAdj

Draw the Deliannnis -Friend circuit and derive the transfer function.

Express 00 ,bandwidth and Q in terms of circuit parameters.

( c) Discuss the attenuation characteristics of ideal and practical low pass and bandpass filters