# GTU Last year question papers

**GUJARAT TECHNOLOGICAL UNIVERSITY**

**BE- V****th ****SEMESTER–EXAMINATION – MAY/JUNE – 2012**

**Subject code: 151003 **

**Subject Name: Integrated Circuits and Applications**

** **

**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 *Cos y = C1/C2*

** ****( 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**

**(b) **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

** ****(d) **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:

_max=0.5 dB,_min= 30 dB._p=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) _0

**( 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=4.7K_, RB=1K_,and C=.05μF,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=200_.Neglect IAdj

** ****(b) **Draw the Deliannnis –Friend circuit and derive the transfer function. Express _0 ,bandwidth and Q in terms of circuit parameters.

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

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