GUJARAT TECHNOLOGICAL UNIVERSITY

ELECTRONICS (10), ELECTRONICS & COMMUNICATION (11),

ELECTRONICS & TELECOMMUNICATION ENGINEERING (12) ANALOG CIRCUIT DESIGN

SUBJECT CODE: 2141002

B.E. 4th

SEMESTER

Type of Course: Circuit Design and Analysis

Prerequisite: Basic knowledge of electronic active and passive components and low frequency

circuit analysis techniques etc

Rationale: This course aims to familiarize students with high frequency analysis of BJT circuits, various

oscillators, differential amplifier, op-amp and its applications, and op-amp based filter circuits.

Teaching and Examination Scheme:

Teaching Scheme Credits Examination Marks Total

Marks L T P C Theory Marks Practical Marks

ESE

(E)

PA (M) ESE (V) PA

(I) PA ALA ESE OEP

4 0 2 6 70 20 10 20 10 20 150

Content:

Sr.

No. Topics

Teaching

Hrs.

Module

Weightage

1

The Transistor at High Frequencies:

Hybrid–pi CE transistor model, Hybrid–pi conductance, Hybrid–pi

capacitances, Validity of hybrid–pi model, Variation of hybrid–pi

parameters, CE short-circuit current gain, Current gain with resistive

load, Single-stage CE transistor amplifier response, Gain-bandwidth

product, Emitter follower at high frequencies

07 14

2

Oscillators:

Sinusoidal oscillators, Phase-shift oscillator, Resonant circuit

oscillators, A general form of oscillator circuit, Wien bridge oscillator,

Crystal oscillators, Frequency stability

05 10

3

Operational Amplifiers:

The basic operational amplifier, The differential amplifier, The emitter-

coupled differential amplifier, Transfer characteristics of a differential

amplifier

03 6

4

Introduction to Operational Amplifiers, Interpretation of Data

Sheets and Characteristics of an Op-amp:

Introduction, Block Diagram representation of a typical op-amp, its

equivalent circuits, types of ICs, Manufacturers’ designations and

package types for ICs, Power supplies for ICs, Interpreting datasheet,

Ideal op-amp, Equivalent circuit of an op-amp, Ideal voltage transfer

curve, Open-loop op-amp configurations

03 6

5

An Op-amp with Negative Feedback:

Voltage series feedback amplifier, Voltage shunt feedback amplifier,

Differential Amplifier

04 8

6 Op-amp Offset Voltage:

Introduction, Input offset voltage, Input bias current, Input offset 04 8

current, Total output offset voltage, Thermal Drift, Effect of variation

in power supply voltages on offset voltage, Change in input offset

voltage and input offset current with time, Other temperature and

supply voltage sensitive parameters, Noise

7

General Linear Applications: DC and AC Amplifiers, AC amplifiers with single supply voltage,

Peaking amplifier, Summing, Scaling and Averaging Amplifier,

Instrumentation Amplifier – its block diagram along with applications,

Differential input and differential output amplifier, Voltage-to-current

converter with floating load (low voltage DC voltmeter, low voltage

AC voltmeter, Diode match finder, Zener diode tester, Light emitting

diode tester), Current-to-voltage converter, Integrator, Differentiator

08 15

8

Comparators and Converters:

Comparator, Zero crossing detector, Schmitt Trigger, Voltage limiters,

Clipper and clampers, Absolute value output circuit, Peak detector,

Sample and hold circuit, Precision rectifier – Half/Full Wave, Square,

Triangular and Saw tooth wave generator, Common mode

configuration and common mode rejection ratio, Slew rate and its

equations, Effect of slew rate in applications

06 11

9

Specialized ICs and its Applications:

a. 555 Timer and its applications: Block diagram, Monostable and Astable multivibrator,

Applications as Frequency divider, Square wave generator

b. Phase Locked Loops and its Applications: Block diagram and operation, Applications as Frequency Multiplier,

Frequency Shift Keying

c. Design of Power Supply: Simple op-amp voltage regulator, Three terminal voltage regulators,

Fixed and adjustable voltage regulators (78XX, LM317), Heat sink,

Dual power supply (LM320, LM317), Basic switching regulator and its

characteristics

04 7

10

Op-amp based Filter Circuits: Classification of filters, Magnitude and frequency scaling, Magnitude

and attenuation characteristics of ideal and practical filters, Design

parameter Q and ω0, Biquad (Universal) filter design, Butterworth low-

pass and high-pass filters – 1st and 2nd order circuits design,

Butterworth pole location, Sallen and key circuit, Butterworth bandpass

filters – frequency transformation, Deliyannis – friend Circuit,

Chebyshev filter characteristics, Band reject filters

08 15

Suggested Specification table with Marks (Theory):

Distribution of Theory Marks

R Level U Level A Level N Level E Level

10 15 15 15 15

Legends: R: Remembrance; U: Understanding; A: Application, N: Analyze and E: Evaluate and above Levels

(Revised Bloom’s Taxonomy)

Note: This specification table shall be treated as a general guideline for students and teachers. The actual

distribution of marks in the question paper may vary slightly from above table.

Reference Books:

1. Electronics Device and Circuits by Jacob Milman, Christos C. Halkias, Chetan D. Parikh, Tata

Macgraw Hill Publication [Second Edition].

2. Op-amps and Linear Integrated Circuits, Ramakant A. Gaikwad, Fourth Edition, PHI.

3. Electronics Principles by Albert Malvino [seventh Edition]

Course Outcomes:

After successful completion of the course students should be able to:

1. To analyze BJT circuits at high-frequency.

2. To analyze various oscillator circuits.

3. To analyze differential amplifier circuit.

4. To interpret and measure op-amp parameters.

5. To analyze various application circuits designed using op-amp.

6. To design Biquad filer circuits.

7. To design Sallen and Key filter circuits.

8. To design Delyiannis-Friend circuits

List of Experiments: 1. To build transistor based RC phase shift oscillator circuit, and measure and verify its frequency of

operation.

2. Measurement of input and output offset voltage of 741 ICs.

3. To configure op-amp in voltage follower mode and to measure its slew rate.

4. To configure op-amp in inverting and non-inverting amplifier mode and measure their gain and

bandwidth.

5. To prepare precision rectifier using op-amp and verify its operation using measurements.

6. To prepare full-wave rectifier using op-amp and verify its operation using measurements.

7. To measure PSRR and CMRR of given op-amp.

8. To design Schmitt trigger circuit using op-amp and take measurements.

9. To design, build astable and monostable multivibrators using 741 IC and verify their operation using

measurements by observing waveforms.

10. To design, build and obtain the frequency responses of first order low pass and band pass active

filters.

11. To build op-amp based Weign bridge oscillator circuit, and measure and verify its frequency of

operation.

12. Design the following amplifiers:

a. A unity gain amplifier

b. A non-inverting amplifier with a gain of ’A’

c. An inverting amplifier with a gain of ‘A’

Apply a square wave of fixed amplitude and study the effect of slew rate on the three type of

amplifiers.

13. Design and test the integrator for a given time constant.

14. Design a second order butter-worth band-pass filter for the given higher and lower cut-off

frequencies.

15. Design and test a notch filter to eliminate the 50Hz power line frequency.

16. Design and test a function generator that can generate square wave and triangular wave output for a

given frequency.

17. Design and test voltage controlled oscillator for a given specification (voltage range and frequency

range).

18. Design and test a Low Dropout regulator using op-amps for a given voltage regulation characteristic

and compare the characteristics with standard IC available in market.

19. Design and test an AGC system for a given peak amplitude of sine-wave output.

20. Design and test a PLL to get locked to a given frequency ‘f’. Measure the locking range of the

system and also measure the change in phase of the output signal as input frequency is varied within

the lock range.

Design based Problems (DP)/Open Ended Problem:

1. Design single stage CE amplifier for high frequency.

2. Design Wien bridge oscillator for a particular frequency.

3. Design voltage series feedback amplifier with op-amp.

4. Design averaging amplifier with op-amp.

5. Design an instrumentation amplifier for particular application.

6. Design zener diode tester with op-amp.

7. Design zero crossing detector circuit using op-amp.

8. Design antilog amplifier.

9. Design touch switch using 555 IC.

10. Design two different color driver using 555 IC.

11. Design a buzzer to indicate end of the class using 555 IC.

12. Design adjustable voltage regulator using LM317 IC.

13. Design 2nd

order High Pass Butterworth filter using op-amp.

Major Equipments and Components:

C.R.O., Function Generator, Power Supply, Multi-meter, Digital Storage Oscilloscope, Experimental

Trainer Kits (e.g. Analog System Lab Kits, Operational Amplifier Trainer Kits, Linear IC Trainer, etc. ),

Bread Board, General Purpose PCB, 741/082 op-amp, 555 Timer, Resistors, Capacitors, Diodes, etc.

List of Open Source Software/learning website:

Ng-spice/Multisim

www.nptel.com

ACTIVE LEARNING ASSIGNMENTS: Preparation of power-point slides, which include videos,

animations, pictures, graphics for better understanding theory and practical work – The faculty will allocate

chapters/ parts of chapters to groups of students so that the entire syllabus to be covered. The power-point

slides should be put up on the web-site of the College/ Institute, along with the names of the students of the

group, the name of the faculty, Department and College on the first slide. The best three works should submit

to GTU.

1

Seat No.: ________ Enrolment No.___________

GUJARAT TECHNOLOGICAL UNIVERSITY BE - SEMESTER–IV (NEW) EXAMINATION – WINTER 2017

Subject Code: 2141002 Date:09/11/2017 Subject Name: Analog Circuit Design Time: 02:30 PM TO 05:00 PM Total Marks: 70 Instructions:

1. Attempt all questions.

2. Make suitable assumptions wherever necessary.

3. Figures to the right indicate full marks.

MARKS

Q.1 (a) Draw BJT based emitter coupled differential amplifier

circuit. How can we improve its CMMR? 03

(b) Derive and analyze expression for common-emitter short

circuit current gain as a function of frequency of input signal. 04

(c) Draw hybrid-pi common-emitter high-frequency BJT model.

Briefly explain importance of each parameter of this model. 07

Q.2 (a) Discuss following parameters of op-amp: 1. Gain-Bandwidth

product, 2. Channel separation for multiple op-amps in a

chip, and 3. Output voltage swing.

03

(b) Sketch equivalent circuit of crystal and discuss its

application in oscillator circuit. Draw crystal based oscillator

circuit.

04

(c) Draw Wien-bridge oscillator circuit and obtain its frequency

of oscillation. 07

OR

(c) State Barkhausen operating principle for circuit to oscillate.

Draw BJT based RC Phase shift oscillator circuit and obtain

its frequency of oscillation.

07

Q.3 (a) Draw op-amp based two-sided voltage limiter circuit and its

response. 03

(b) Define and explain measurement techniques/setups for

following terms of op-amp: 1. CMRR and 2. Slew Rate. 04

(c) For op-amp based non-inverting amplifier, obtain

expressions for RIF, ROF, and ACL. Assume op-amp

parameters as: open loop gain - A, input resistance - Ri and

output resistance - RO.

07

OR

Q.3 (a) Which are the important parameters of comparator? Can we

use Schmitt trigger circuit as a comparator? Briefly justify

your answer.

03

(b) Define and explain measurement techniques/setups for

following terms of op-amp: 1. PSRR and 2. Input Offset

Voltage.

04

(c) For op-amp based inverting amplifier, obtain expressions for

RIF, ROF, and ACL. Assume op-amp parameters as: open loop

gain - A, input resistance - Ri and output resistance - RO.

07

Q.4 (a) Draw block diagram of phase locked loop (PLL) and briefly

explain its working. State applications of PLL. 03

(b) How can we convert voltage to current using op-amp for

grounded load? Draw necessary circuit and justify your 04

2

answer with mathematical proof.

(c) Which are the different factors contributing to output offset

voltage in op-amp based circuit? Discuss steps for the design

of input offset voltage compensating network along with

necessary diagram.

07

OR

Q.4 (a) Draw block diagram of 555 timer IC and briefly explain its

working. 03

(b) How can we perform integration of input voltage using op-

amp? Draw necessary op-amp based basic integrator circuit

and carry out mathematical analysis.

04

(c) What is/are the advantages of op-amp based rectifier

circuits? Analyze quantitatively op-amp based full wave

rectifier circuit with necessary diagrams.

07

Q.5 (a) What do you understand by magnitude and frequency

scaling? How is it used in the design of filter circuit? Explain

with example.

03

(b) Sketch frequency response of band-pass filter circuit. How

many minimum poles and zeros are required to realize band-

pass frequency response? Justify your answer.

04

(c) Develop 2nd order op-amp based Biquad circuit for low-pass

filter from the transfer function with ω0 = 1 rad/sec. 07

OR

Q.5 (a) Draw circuit schematic of four-op-amp Biquad circuit and

state the condition under which we can realize notch-filter. 03

(b) Sketch frequency response of high-pass filter circuit. How

many minimum poles and zeros are required to realize high-

pass frequency response? Justify your answer.

04

(c) Draw Sallen and key low-pass filter circuit and obtain its

transfer function. Discuss one of the design methods for this

circuit.

07

*************

1

Seat No.: ________ Enrolment No.___________

GUJARAT TECHNOLOGICAL UNIVERSITY BE - SEMESTER–IV (NEW) - EXAMINATION – SUMMER 2017

Subject Code: 2141002 Date: 30/05/2017 Subject Name: Analog Circuit Design Time: 10:30 AM to 01:00 PM Total Marks: 70 Instructions:

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

MARKS

Q.1 Short Questions 14

1 Explain the behavior of transistor at high frequency.

2 Which Amplifier is often used to drive capacitive loads.

3 What is the suitable frequency range for wein bridge oscillator?

4 What is differential amplifier? How it is different from conventional

amplifier?

5 Which type of negative feedback is present in inverting configuration?

6 Explain procedure of offset-nulling in op-amp.

7 Explain any one application of I-V converter in brief.

8 How op-amp is used as a summing amplifier?

9 Enlist the applications of comparator and explain PLD.

10 What is multivibretor? Classify different multivibretors.

11 Define and explain the ‘Lock range’ and ‘Capture range’.

12 What is the difference between shunt and series regulator?

13 Explain the necessaity of high order filters.

14 What is the difference between active and passive filters?

Q.2 (a) Explain Barkhausen criterion for oscillation in brief. 03

(b) Design RC phase oscillator for the frequency of 2 KHz. 04

(c) Draw op-amp based wein bridge oscillator. Obtain frequency of

oscillation and discuss amplitude stabilization for same. 07

OR

(c) Derive the expression for the frequency for the RC phase shift oscillator

using transistor. 07

Q.3 (a) A Hartley oscillator circuit has a tank circuit inductance of

L1=L2=100µH. It is required to produce oscillations at 50 KHz. Obtain

the exact value of the tank circuit capacitance for the above requirement.

03

(b) State the relation between hybrid-Π and h-parameters. 04

(c) Draw and explain with necessary figure the single stage CE amplifier

response. Also explain the significance of GB product. 07

OR

Q.3 (a) Derive the necessary equation of gain for All pass filter. 03

(b) Design on Op-Amp Schmitt trigger with LTP = 2V, UTP = 4V and

Vsat= ±10 V. 04

(c) Draw circuit diagram of differential amplifier with three op-amps and

derive expression for its output signal as a function of input signals. 07

Q.4 (a) Define PSRR of an op-amp. If PSRR of an op-amp is 150µv/v and

supply voltage changes from +10v to +12v, what is the change in Vio. 03

(b) An op-amp as inverting amplifier is driven by 10 V peak to peak sine 04

2

wave. Supply voltage of op-amp is +/- 15V. Draw input and output

waveforms and give your comments.

(c) Prove that output is integral function of Input.

07

OR

Q.4 (a) Define the following. (i) CMRR (ii) Slew Rate (iii) Offset voltage. 03

(b) Draw and explain working of op-amp based Full wave rectifier circuit. 04

(c) Explain voltage to current converter with floating load. Based on that

show low voltage DC voltmeter circuit and discuss it. 07

Q.5 (a) Discuss fixed and adjustable voltage regulator with necessary circuit

diagrams. 03

(b) For an astable multivibretor using 555 timer, RA=4.7KΩ, RB= 1KΩ and

C=0.05µF, determine the positive pulse width, negative pulse width and

free running frequency.

04

(c) Design and explain the 2nd order low pass butterworth filter. Derive the

equation of gain for the same. 07

OR

Q.5 (a) Calculate output frequency fo, lock range and and capture range of a

PLL if RT=1KΩ, CT=0.1µF and filter capacitor C=10 µF and V=20v. 03

(b) Explain the magnitude and phase response of low pass function of

biquad circuit. 04

(c) Explain with the circuit diagram and waveforms, the monostable

multivibretor using 555 timer. Design the same for output pulse width of

10ms.

07

*************

1

Seat No.: ________ Enrolment No.___________

GUJARAT TECHNOLOGICAL UNIVERSITY BE - SEMESTER–IV(New) • EXAMINATION – WINTER 2016

Subject Code:2141002 Date:18/11/2016

Subject Name:Analog Circuit Design

Time: 02:30 PM to 05:00 PM Total Marks: 70 Instructions:

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

Q.1 Short Questions 14

1 Applications of op-amp

2 Write the equation of gain with positive feedback.

3 Define slew rate.

4 List three open loop op-amp configurations.

5 The internal capacitances of a transistor are effective at _____ frequencies.

6 Which are two special cases of inverting amplifier?

7 Write the equation of CMRR in dB.

8 Name the pins of IC 555.

9 Give classification of multivibrators.

10 Applications of PLL

11 Define cut off frequency.

12 Draw frequency response of Band pass filter.

13 List three types of linear IC packages.

14 List the types of voltage regulators.

Q.2 (a) Explain Hybrid –π capacitances. 03

(b) What is an oscillator? Explain Bark hausen criterion for oscillator. 04

(c) Draw Hybrid –π equivalent circuit for CE transistor. Also derive the equation of 07

input conductance gb’e.

OR

(c) Explain the working of Hartely oscillator. 07

Q.3 (a) What is differential amplifier? 03

(b) Define the following parameters of Op-Amp: 04

(i) Input bias current

(ii) common mode gain

(iii) Input offset voltage

(iv) Output offset voltage

(c) What is op-amp. List out characteristics of ideal op-amp. 07 OR

(a) Draw and explain block diagram of op-amp. 03

(b) Derive the equation of voltage gain for inverting and non inverting configuration. 04

2

(c) Explain all three open loop op-amp configurations. 07

Q.4 (a) Draw block diagram of SMPS. 03

(b) Explain zero crossing detector with ckt diagram and waveforms. 04

(c) Explain application of op-amp(inverting) as summing, scaling and averaging 07

amplifier.

OR

(a) How op-amp can be used as an integrator? 03

(b) Explain instrumentation amplifier in brief. 04

(c) Explain working of 555 timer based monostable multivibrator. 07

Q.5 (a) What is difference between active and passive filters? 03

(b) Draw ideal characteristics of all basic filters. 04

(c) Show how Bi-quad circuit can be used as a universal filter? 07

OR

(a) Briefly explain Notch filter. 03

(b) Discuss magnitude scaling and frequency scaling in filter design. 04

(c) Draw sallen-key LPF and derive its transfer function. 07

3

Seat No.: ________ Enrolment No.___________

GUJARAT TECHNOLOGICAL UNIVERSITY BE - SEMESTER–IV(New) EXAMINATION – SUMMER 2016

Subject Code:2141002 Date:26/05/2016 Subject Name:Analog Circuit Design Time:10:30 AM to 01:00 PM Total Marks: 70 Instructions:

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

Q.1 Short Questions 14

1 Why differential amplifier is necessary?

2 Why does amplifier gain reduce in BJT amplifier?

3 What is an op-amp?

4 List three open loop op-amp configurations.

5 What is the concept of Virtual ground

6 What is an instrumentation amplifier?

7 Application of voltage to current converter

8 Draw the circuit diagram of ideal op-amp

9 What is PSRR?

10 What are the applications of differentiator?

11 What do you understand by precision full wave rectifier circuit?

12 What is the major difference among SSI, MSI, LSI and VLSI ICs?

13 List the different types of voltage regulators.

14 What is error voltage?

Q.2 (a) A Hartley oscillator circuit has a tank circuit inductance of L1=L2=100 µH. It is

required to design the oscillator to produce oscillations at50 KHz. Obtain the

exact value of the tank circuit capacitance for the above said requirement.

03

(b) Write short note on validity of hybrid-π model. 04

(c) Explain Wien bride oscillator with neat sketch. What determines the frequency of oscillation? Will oscillations take place if the bridge is balanced?

07

OR

(c) List the parameter those affecting to the transistor at high frequencies. Draw the

hybrid π model for CE configuration and explain it. Also derived the equation for

any two above listed parameter for CE configuration.

07

Q.3 (a) What are the different important parameters of comparator circuit? 03

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

(i) Input bias current.

(ii) Common Mode Rejection Ratio.

(iii) Input offset voltage.

(iv) Output offset voltage

04

(c) Derive gain equation for Op Amp for inverting and non inverting mode and

derive equation for Common mode rejection Ratio (CMRR). Why CMRR should

07

be ideally high.

OR

Q.3 (a) Define slew rate of an Op-Amp .What are its causes? 03

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

inverting configuration.

04

(c) 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 ideal and practical integrators.

07

Q.4 (a) Equivalent circuit of a non-inverting amplifier. 03

(b) A non inverting amplifier with a gain of 10 is to be driven with 2 volts peak to

peak sine wave of 20 kHz frequency. What should be the minimum slew rate of

the op-amp to have the distortion free output?

04

(c) Draw the non-inverting Schmitt trigger comparator circuit and explain the threshold

levels and hysteresis. 07

OR

Q.4 (a) What do you understand by precision rectifier? 03

(b) Comparison of linear and switching mode regulators. 04

(c) An astable multivibrator is to be designed for getting rectangular waveform with

tON=0.6 ms. Draw the circuit diagram with various component values. Also

calculate frequency of oscillations and duty cycle. Assume total time period (T) to

be 1 ms. Assume C=0.1µs

07

Q.5 (a) State the properties of Butterworth filter 03

(b) What is thermal drift? How does it affect the performance of an op-amp circuit? 04

(c) Design a high pass filter with a cut off frequency of 10KHz with a pass band gain

of 1.5. Also plot the frequency response for the designed filter. C=0.02µF

07

OR

Q.5 (a) Define PSRR of an op-amp .In an op-amp PSRR is 150µV/V. If supply voltage is

changed from +10V to +12V, what is the change in input offset voltage Vio?

03

(b) What is the difference between active and passive filter. 04

(c) Explain wide band-pass filter with necessary circuit, derivation and waveforms

07

1

Seat No.: ________ Enrolment No.___________

GUJARAT TECHNOLOGICAL UNIVERSITY BE - SEMESTER–IV (New) EXAMINATION – WINTER 2015

Subject Code:2141002 Date:19/12/2015

Subject Name: Analog Circuit Design

Time: 2:30pm to 5:00pm 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) Draw the differential amplifier circuit using two op-amp. State advantage of

one additional op-amp in that. Show how its output is related to input using

necessary derivations.

07

(b) Design the wein bridge using JFET, to produce a sinusoid output of frequency

2KHz. The FET has gm =2.5 ms and µ=35. 07

Q.2 (a) Explain the working of Hartley oscillator. Derive the expression for frequency

of oscillation. 07

(b) Derive the expression for current gain with resistive load using hybrid Π model. 07

OR

(b) The following low frequency parameters are known for a given transistor at

Ic=1.3 mA, VCE= 10V at room temperature and the h-parameters are as

follows.

hfe=50, hie=1100, hre=2.5x10-4, hoe=24μA/V.

At the same point fT= 50 MHz and Cob=3pF. Compute all the values of hybrid π

parameters of CE transistor model.

07

Q.3 (a) Explain the positive full wave rectifier using op-amp.

07

(b) Draw the hybrid Π common emitter transistor model. Also derive the

expression for input conductance. 07

OR

Q.3 (a) Explain working of 555 timer based Monostabe multivibrator. Design the same

for the output pulse width of 10 ms. 07

(b) Prove that output is integral function of Input.

07

Q.4 (a) Explain the basic differentiator using an op-amp. What are the problems

associated with this configuration? How they are overcome? 07

2

(b) Explain how op-amp can be used to generate free running square wave with

necessary circuit diagram and waveforms. Show how time period can be

calculated.

07

OR

Q.4 (a) What is PLL? Explain operation of PLL with basic blocks and mention any four

applications of it in radio communication. 07

(b) What is need of clipper circuit? Explain op-amp as a positive and negative

clipper along with necessary waveforms. 07

Q.5 (a) Explain the working of a Schimitt trigger using op-amp 07

(b) Analyze second order butterworth high Pass filter. Draw its frequency response

and state design procedure. 07

OR

Q.5 (a) Derive transfer function of Sallen-key low pass filter 07

(b) Sketch Delyiannis-Friend circuit and obtain its transfer function.

. 07

*************

1

Seat No.: ________ Enrolment No.___________

GUJARAT TECHNOLOGICAL UNIVERSITY BE - SEMESTER– IV(NEW) EXAMINATION – SUMMER 2015

Subject Code:2141002 Date:26/05/2015 Subject Name: Analog circuit design Time: 10:30am-1.00pm 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) Draw Hybrid -π equivalent circuit for CE transistor. Also derive the equation of

input conductance gb’e. 07

(b) What is an oscillator? Explain the concept of oscillation with Barkhausen criteria. 07

Q.2 (a) A BJT has following parameters. hie=1 kΩ, hfe=100, hre and hoe are negligible. Cc=3pF. Collector current is 10 mA at room temperature. The short ckt. Current gain is 10 at frequency 10 MHz. Calculate values of fα, fβ and fT.

07

(b) Derive the expression for voltage gain, input resistance, output resistance of an inverting amplifier using op-amp with negative voltage shunt feedback.

07

OR (b) Draw circuit diagram of differential amplifier with two op-amps and derive

expression for its output signal as a function of input signals. Also derive expressions of input resistance faced by each input signal.

07

Q.3 (a) What are the characteristics of an ideal op-amp? Draw its equivalent circuit of op-amp and explain voltage transfer curve.

07

(b) Design an op-amp based practical differentiator circuit to differentiate an input signal that varies in frequency from 10 Hz to 1 kHz. Draw output waveform of the designed differentiator circuit for an input signal with 2V peak-to-peak amplitude with 1 kHz frequency.

07

OR Q.3 (a) What is an instrumentation amplifier? Explain with the help of neat diagram the

operation of an instrumentation amplifier employing three basic op-amps. 07

(b) Design an input offset voltage compensating network for the inverting amplifier with R1 = 100Ω and RF = 4.7 k Ω. The op-amp is LM307 with Vio = 10 mV and supply voltages ± 10V.

07

Q.4 (a) Explain SMPS (switched mode power supply) with necessary circuit diagram and waveforms.

07

(b) Which type of feedback is used in Schmitt trigger circuit? Discuss its operation and derive expressions for lower and upper threshold voltage. Design the Schmitt trigger circuit for upper and lower threshold voltage equal to 25 mV and -25 mV. Op-amp maximum output voltages are ± 14 V. Take ± 15V as op-amp supply voltage.

07

Q.4 (a) Explain the working of Monostable multivibrator using IC 555. 07

(b) Explain how op-amp can be used to generate free running square wave with necessary circuit diagram and waveforms. Show how time period can be calculated.

07

Q.5 (a) Discuss magnitude and frequency scaling in filter design. 07

2

(b) Draw Sallen-key LPF circuit and obtain its transfer function. 07

OR Q.5 (a) Draw first order butterworth LPF circuit and derive the equation of Gain. Also

draw the frequency response of it. 07

(b) What is differential amplifier? Describe the operation of emitter coupled differential amplifier.

07

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