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1 VALLIAMMAI ENGINEERING COLLEGE SRM Nagar, Kattankulathur DEPARTMENT OF ELECTRONICS & COMMUNICATION ENGINEERING QUESTION BANK SUBJECT : EC6404 LINEAR INTEGRATED CIRCUITS SEM / YEAR: IV / II year B.E. Unit I BASICS OF OPERATIONAL AMPLIFIERS Current mirror and current sources, Current sources as active loads, Voltage sources, Voltage References, BJT Differential amplifier with active loads, Basic information about op amps Ideal Operational Amplifier General operational amplifier stages and internal circuit diagrams of IC 741, DC and AC performance characteristics, slew rate, Open and closed loop configurations. Part A Q.No Questions BT Level Competence 1. Describe offset voltage of an operational amplifier 2. Define CMRR. 3. Explain the concept that what do you mean by balanced and unbalanced output? 4. What is an ideal op amp? 5. Explain thermal drift? 6. Write short note about current mirror with magnification. 7. Describe slew rate and what causes the slew rate? 8. State loading effect? How can you reduce it? 9. Why do we use R comp resistor? 10. What is the gain cross over and phase cross over frequencies? 11. Categorize the characteristics of an ideal op amp. 12. Give the internal block diagram of an op amp. 13. Draw the pin diagram of IC Mention the importance of input off set current. 15. Write note about input bias current. 16. the draw backs of using large R C in differential amplifier. 17. Brief the necessity of active loads preferred than passive loads in the input stage of an operational amplifier. 18. Justify that, why IC741 op amp not used for high frequency applications? 19. Calculate the maximum distorted amplitude that a sine wave input of 10kHz, can produce at the output of an op amp whose slew rate is 0.5v/μsec. 20. A Differential amplifier has a differential voltage gain of 2000 and

2 common mode gain of 0.2. Determine CMRR. Part B 1. Define and explain slew rate. Derive its equation. Also explain method adapted to improving slew rate. 2. (i) Write down the characteristics and their respective values of an ideal operational amplifier (6) (ii) Draw the circuit of basic current mirror and explain its operation.(10) 3. (i) Describe about output offset voltage. Explain methods to nullify offset voltage.(8) (ii) With neat circuit diagram, explain the operation of Voltage reference circuit using temperature compensation.(8) 4. (i) Discuss on current mirror with magnification.(8) (ii) Use appropriate block diagram, explain the general stages of an Op Amp IC.(8) 5. (i) Explain in detail about frequency compensation techniques applied to operational amplifiers.(8) (ii) Briefly describe about multiple current sources.(8) 6. (i) Draw the circuit of basic current mirror and explain its operation(8) (ii) Give the detail the DC analysis of a basic differential amplifier or obtain the expression for operating point values of a basic differential amplifier.(8) 7. Obtain the expression for differential gain, common mode gain, CMRR, R I and R O of an emitter coupled differential amplifier. 8. (i) Sketch the Wilson current source and give detailed note about it.(8) (ii) Using suitable diagram and necessary equations, explain the concept of Widlar current source used in op amp circuit. (8) 9. Derive the transfer characteristics of dual input differential amplifier showing the linear and limiting regions. Comment on the same 10. (i) A square wave peak to peak amplitude of 50mV has to be amplified to a peak to peak amplitude of 3V, with rise time of 4 μs or less. Can IC741 be used? (8) (ii) A IC741 Op Amp whose slew rate is 0.5V/μs is used as an inverting amplifier with a gain of 50.The voltage gain Vs frequency curve of IC741 is flat up to 20 khz. What maximum peak to peak input signal can be applied without distorting the output. (8) UNIT II APPLICATIONS OF OPERATIONAL AMPLIFIERS Sign Changer, Scale Changer, Phase Shift Circuits, Voltage Follower, V to I and I to V converters, adder, subtractor, Instrumentation amplifier, Integrator, Differentiator, Logarithmic amplifier, Antilogarithmic amplifier, Comparators, Schmitt trigger, Precision rectifier, peak detector, clipper and clamper, Lowpass, high pass and band pass Butterworth filters.

3 PART A Q.No Questions BT Level Competence 1. What are the advantages of variable transconductance technique? 2. Write the output expression for following: inverting & noninverting amplifiers, Integrator and differentiator. 3. Mention the applications of voltage to current converters. 4. Brief note about an instrumentation amplifier 5. Compare the performance of inverting and non inverting operational amplifier configurations. 6. Give the applications of inverting & non inverting amplifiers. 7. Draw the inverting & non inverting amplifiers with appropriate equatons. 8. List the applications for each of the following circuits: Voltage follower, Peak detector, Schmitt trigger, Clamper. 9. Why integrators are preferred over differentiators in analog computers? 10. Summarize the frequency expressions for LPF, HPF and BPF. 11. Enumerate the advantages & disadvantages of passive filters? 12. Sketch the opamp integrator & differentiator circuit with necessary equation. 13. Define comparator 14. Illustrate some of the important features of an instrumentation amplifier. 15. Construct an adder circuit using op amp to get the output expression as Vo = (0.1V1 +V2+5V3) 16. Demonstrate the need for frequency compensation in practical op amps 17. Show the necessity of active guard drive in an instrumentation amplifier. 18. Find the output voltage of the following circuit. Given R1 =R2 = 10kΩ and Rf = 100

4 19. How does precision rectifier differ from the conventional rectifier? 20. Design an amplifier with a gain of 10 and input resistance equal to 10 kω. PART B 1. Explain the operation of Instrumentation amplifier with suitable diagram. 2. (i) Using appropriate equations discuss about the working of Half wave Precision Rectifier. (10) (ii) Examine the principal of operation of Voltage follower With the neat circuit diagram and mathematical expressions. (6) 3. (i) Draw and explain the operation of Triangular wave generator. (6) (ii) Write short notes on second order Low Pass Butterworth filter (Sallen key filter).(10) 4. (i) With neat sketch explain the working of Full wave Precision Rectifier in detail.(8) (ii) Sketch the Integrator circuit and explain the working principle in detail. (8) 5. (i) Design an OP AMP based first order active low pass filter. (8) (ii) a second order Butterworth LPF having upper cut off frequency 1 khz. Determine the frequency response. (8) 6. Construct the basic circuit using op amp for the mathematical operation of differentiation and explain in detail. 7. (i) Draw and explain the circuit of a voltage to current converter if the load is a) Floating b) Grounded (8) (ii) With the neat circuit diagram and mathematical expressions, explain the operation of Scale changer. (8) 8. Derive the expression for log computation using opamp and explain necessary circuit diagram. 9. i)with neat diagram explain the operation of Schmitt trigger.(8) ii)design a wide band filter having F L =400Hz, F H =2kHz and pass band gain of 4.Find the value of Q of filter(8) 10. (i) Conclude that how antilog computations are performed using IC 741 explain using circuits and necessary equations. (8) (ii) Investigate the operation of Inverting adder and Non inverting adder With the neat circuit diagram and mathematical expressions. (8) UNIT III ANALOG MULTIPLIER AND PLL Analog Multiplier using Emitter Coupled Transistor Pair Gilbert Multiplier cell Variable transconductance technique, analog multiplier ICs and their applications, Operation of the basic PLL, Closed loop analysis,

5 Voltage controlled oscillator, Monolithic PLL IC 565, application of PLL for AM detection, FM detection, FSK modulation and demodulation and Frequency synthesizing. Q.N o PART A Questions BT Level Competence 1. List the basic building blocks of PLL. 2. Define lock in range &capture range of a PLL. 3. What is Pull in time? 4. For perfect lock, what should be the phase relation between the incoming signal and VCO output signal? 5. Name the classification of phase detector. Write about switch type phase detector. 6. Illustrate the problems associated with switch type phase detector 7. Why VCO is also called as V to F converter? 8. On what parameters does the free running frequency of VCO depend on? 9. Give the expression for the VCO free running frequency. 10. Demonstrate Voltage to Frequency conversion factor. 11. Identify the purpose of having a low pass filter in PLL. 12. Discuss the effect of having large capture range. 13. some typical applications of PLL 14. How would you explain compander IC? Give some examples. 15. Identify the merits of companding 16. Tell the applications of OTA. 17. Estimate four quadrant multiplier. 18. What is the necessity of modulation? 19. Draw the circuit of AM detector using PLL. 20. Compare the advantages & disadvantages of monolithic PLLs over Discrete PLLs? PART B 1. How would you describe the block diagram of PLL and derive the expression for Lock range and capture range. (16) 2. Illustrate the operation of VCO with neat block diagram. Also derive an expression for f0. (16) 3. (i) the Gilbert s four quadrant multiplier cell with a neat circuit diagram. (8) (ii) Identify how a frequency doubler can be realized using this cell. (8) 4. Discuss any three applications of PLL in detail. (16)

6 5. Explain the purpose and functioning of (i) Variable trans conductance multiplier(8) (ii) Frequency synthesizer(8) 6. ii) Estimate the working principle of operational Transconductance Amplifier (OTA). (10) ii) Explain the application of VCO for FM generation. (6) 7. i)define capture range and lock range. (4) ii) Explain the process of capturing the lock and also derive for capture range and lock range. (12) 8. i) How would you explain the working of a VCO. (8) ii) Derive the expression for voltage to frequency conversion factor. (8) 9. Determine how the IC 565 PLL can be used as a Frequency multiplier/divider. (16) 10. (i) Outline the multiplier cell using emitter coupled transistor pair. (8) (ii) that the output voltage is proportional to the product of the two input voltages and state their limitations. (8) UNIT IV ANALOG TO DIGITAL AND DIGITAL TO ANALOG CONVERTERS Analog and Digital Data Conversions, D/A converter specifications weighted resistor type, R 2R Ladder type, Voltage Mode and Current Mode R 2R Ladder types switches for D/A converters, high speed sample and hold circuits, A/D Converters specifications Flash type Successive Approximation type Single Slope type Dual Slope type A/D Converter using Voltage to Time Conversion Over sampling A/D Converters Q. No PART A Questions BT Level Competence 1. How would you classify ADCs. 2. List the direct type ADCs. 3. What is the function of integrating type converter? List out some integrating type converters. 4. Brief the principle of operation of successive Approximation ADC. 5. What are the main advantages of integrating type ADCs? 6. Where are the successive approximation type ADC s used? 7. Compare the advantages and drawbacks of a dual slop ADC. 8. Distinguish between conversion time and settling time. 9. Estimate your opinion of resolution of a data converter. 10. Define accuracy of converter. 11. Brief about monotonic DAC? 12. Summarize delta modulation. 13. How would you justify which type of ADC is the fastest? 14. Spell the principle of operation of voltage to time conversion?

7 15. Calculate the values of LSB and MSB for an 8 bit DAC for 0V to 10V range. 16. Construct granular error and slope overload error. 17. Solve an 8 bit DAC has an output voltage range of V. Calculate its resolution. 18. Invent the number of comparators required for realizing a 4 bit flash ADC. 19. Compare and contrast binary ladder and R 2R ladder DAC. 20. Model Sample and hold circuit, Why is it needed? PART B 1. With neat internal diagram, explain the following (i) Dual slope ADC (8) ii) Successive Approximation ADC. (8) 2. a) Estimate the working of R 2R ladder type DAC. (8) b) Compare binary weighted DAC with R 2R ladder network DAC. (8) 3. With circuit schematic explain analog switches using FET. (16) 4. (i) What are the different sources of error in DAC(8) (ii) Analyse the types of errors in DAC(8) 5. Show the working principle of DM and ADM. (16) 6. Discuss in detail about the following Digital to Analog conversion techniques. i) R 2R ladder type DAC (8) ii) Weighted resistor DAC(8). 7. (i)draw the diagram of sample and hold circuit. (8) (ii)state how you will reduce its hold mode droop. (8) 8. Design a 4 bit binary weighted resistor DAC for the following specifications: Use LM741 op amp, R = 10kΩ, Vref =2.5V and full scale output = 5V. (16) 9. A dual slope ADC has a full scale input of 2 Volts.It uses an integrating time of 10ms and integrating capacitor of 0.1µf.the maximum magnitude of the integrator output should not exceed 3V. Calculate the value of the integrating resistor. (16) 10. i)explain the working of a voltage to time converter and voltage to frequency converter. (8) ii) Construct the working of dual slope ADC (8) UNIT V WAVEFORM GENERATORS AND SPECIAL FUNCTION ICS Sine-wave generators, Multivibrators and Triangular wave generator, Saw-tooth wave generator, ICL8038 function generator, Timer IC 555, IC Voltage regulators Three terminal fixed and adjustable voltage regulators - IC 723 general purpose regulator - Monolithic switching regulator, Switched capacitor filter IC MF10, Frequency to Voltage and Voltage to Frequency converters, Audio Power amplifier, Video Amplifier, Isolation Amplifier, Opto-couplers and fibre optic IC. PART A Q.No Questions BT Level Competence

8 1. What are the different protection circuits inside the monolithic IC regulator? 2. List the applications of opto coupler. 3. State the two conditions for oscillation. 4. Give the classification of voltage regulators 5. What is a switching regulator? 6. List the applications of 555 timer in Monostable mode of operation. 7. What are the three different wave forms generated by ICL8038? 8. Mention the need for current limiting in voltage regulators? 9. Compare Linear regulator and Switched mode regulator. 10. Give some examples of monolithic IC voltage regulators. 11. Draw the functional block diagram of IC 723 regulator. 12. Compare Audio Power Amplifier and Video Amplifier. 13. How would you classify an opto-coupler? List the characteristics of opto-couplers. 14. Define line and load regulation of a regulator. 15. In a Astable multivibrator of 555 times R A =606kΩ and C=0.1μF. Calculate (a) t HIGH (b)t LOW (c) free running frequency (d) duty cycle (D). 16. How does switched capacitor emulate resistor? 17. With reference to a VCO, define voltage to frequency conversion factor Kv. 18. In a monostable multivibrator using 555 timer, R=100kΩ and the time delay is 100ms.Find the value of C. 19. List the types of Multivibrator. 20. What is the purpose of connecting a capacitor at the input and output side of an IC voltage regulator? PART B 1. Write a short notes on i) Opto couplers and Switched capacitor filter (10) ii) Isolation amplifier (6) 2. (i)explain the functional diagram of LM 380 power amplifier. (10) (ii)write the essential characteristics of power amplifier. (6) 3. What is 555 timer? Explain the working of 555 timer as Monostable Multivibrator (10) (ii) Derive an expression for the frequency of oscillation with relevant waveforms.(6)

9 4. (i) What is a Switching regulator? Explain the operation of switching regulator with neat diagram. (10) (ii) Write short note on frequency to voltage converters.(6) 5. (i) Explain the working of Astable Multivibrator using op-amp.(10) (ii) Explain any one application of Astable Multivibrator(6) 6. i)design a phase shift oscillator to oscillate at 100 Hz. (6) ii)describe Monostable multivibrator with necessary diagrams and derive for ON time and recovery time.(10) 7. (i) Explain the working of Linear Voltage regulator with neat circuit diagram using op-amps.(10) (ii) List the characteristics of voltage regulator(6) 8. (i)briefly describe about monolithic switching regulator.(10) (ii) Write short note on voltage to frequency converters.(6) 9. (i)explain in detail the function of 555 timer in Astable mode(10) (ii)derive the expression for the pulse width. (6) 10. (i) What is the basic principle of function generator? Draw the schematic of ICL 8038 function generator and discuss its features.(10) (ii)find the expression for the frequency of a triangular waveform generator and explain the circuit.(6) BTL3

VALLIAMMAI ENGINEERING COLLEGE SRM Nagar, Kattankulathur DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING QUESTION BANK IV SEMESTER

VALLIAMMAI ENGINEERING COLLEGE SRM Nagar, Kattankulathur 603 203 DEPARTMENT OF ELECTRONICS AND COMMUNICATION ENGINEERING QUESTION BANK IV SEMESTER EC6404 LINEAR INTEGRATED CIRCUITS Regulation 2013 Academic