EC6404-LINEAR INTEGRATED CIRCUITS Question bank UNIT-I PART-A 1. What are the advantages of an IC over discrete components?

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1 EC6404-LINEAR INTEGRATED CIRCUITS Question bank UNIT-I PART-A 1. What are the advantages of an IC over discrete components?(apr-2014)(apr- 2013,Nov-2014) 2. State an Monolitihic ICs.(Apr-2010,Nov-2014) 3. State the limitations of discrete circuits.(apr-2013) 4. What is the maximum undistorted amplitude,that a sine input of 10kHz,can produce,at the output of opamp whose slewrate is 0.5 V/µs?(Nov-2012) 5. What is the maximum undistorted amplitude 6. Compare the features of monolithic & hybrid technologies. 7. What are the different types of packaging techniques of Ics? 8. What is a current mirror & why is it called so?(apr-2010) 9. What is a current mirror with magnification?(nov-2011) 10. What are the advantages of an active load? 11. What is the need of a level translator in an opamp? 12. What are voltage references? 13. Explain the concept of virtual ground. 14. Draw the inverting and non-inverting amplifier with corresponding input & output waveforms for the same. 15. The OP-77 has a gain of twelve million. Express the gain in db. 16. Define CMRR. (Apr-2013,Nov-2010,Apr-2011) 17. What are the requirements to be met for a good current source?(may-2012) 18. List the methods of realizing high Ri in a differential amplifier?(may-2012) 19. Define PSRR. 20. What are the ideal characteristics of op-amp? 21. Draw the equivalent circuit of practical op-amp? 22. Discuss the nature of output in open loop configuration of op-amp? 23. Write the gains of inverting and non-inverting op-amp? 24. What is a differential amplifier? 25. What is difference mode and common mode gains? 26. Draw the block diagram of Operational Amplifier. 27. What is input bias current? 28. Define unity gain bandwidth of an opamp. 29. What is bias current compensation? 30. What is input offset current? 31. What is input offset voltage? 32. Define thermal drift. 33. What is the need for frequency compensation?(nov-2010) 34. What is dominant pole compensation? 35. What is pole zero compensation? 36. What do you mean by internal compensation? 37. Define slew rate. (Apr-2014,Nov-2010,Nov-2011) 38. What does the term roll off mean?

2 39. What is the advantage of widlar current source over constant current source? 40. Mention the advantages of Wilson current source. 41. What do you mean by a band-gap referenced biasing circuit? 42. In practical op-amps, what is the effect of high frequency on its performance? 43.Why are active loads preferred than passive loads in the input stage of an operational amplifier?( Nov-2010) 44. Compare the performance of inverting and non inverting operational amplifier Configurations(Nov-2010) PART-B 1. Explain the integral circuit diagram of IC741.Discuss its AC and DC performance characteristics.(nov-2010,nov-2011) 2. Derive expressions for outputs, input impedance and gain for an inverting amplifier. 3. Explain the need of large CMRR value. How is it achieved? Explain in detail and derive the expression for CMRR in a differential amplifier using opamp? (Apr-2010) 4. Explain the difference between constant current source and current mirror. 5. Explain the operation of a Wilson& Widlar current source with a neat diagram.(nov-2011,apr-2011) 6. Explain the concept of the use of Voltage reference. Also explain the function of voltage reference source using temperature compensation and avalanche diode reference(may-2012). 7. Compare different configurations of Differential amplifier(apr-2013) 8. Explain in detail the inverting & non-inverting amplifier and derive the expression for closed loop gain. 9. For a dual input, balanced output differential amplifier, Rc=2.2.KΩ, RE=4.7KΩ, Rs1=Rs2=50Ω. The supply voltages are ±10V. the hfe for the transistor is 50. Assume silicon transistors and hie =1.4KΩ. Determine the operating point values, differential gain, common mode gain and CMRR. (Apr-2013) 10. Explain the Non Ideal DC characteristics of op-amp.(may-2012) 11. Explain the Non Ideal AC characteristics of op-amp.(nov-2014) 12. Explain the frequency compensation techniques in detail. 13. For a non inverting amplifier R1=1KΩ, Rf=10KΩ, (i) Calculate the maximum output offset voltage due to Vos. Given Ib =300nA, Ios=50nA, Vos =10mv, Ios =9nA (ii) Calculate the value of Rcomp needed to reduce the effect of Ib (iii) Calculate the maximum output offset if Rcomp is connected in the circuit. 14. For an inverting amplifier R1=1KΩ? Rf=10KΩ? (i) Calculate the maximum output offset voltage due to Vos.Given Ib =300nA, Ios=50nA,

3 Vos =10mv, Ios =9nA (ii) Calculate the value of Rcomp needed to reduce the effect of Ib (iii) Calculate the maximum output offset if Rcomp is connected in the circuit. 15. In a non-inverting amplifier if R1=5KΩ, Rf=20KΩ& Vi=1V and RL=5KΩ is connected at the output. Calculate output voltage, Load current and closed loop gain. 16. Draw the schematic of an emitter coupled differential amplifier. Explain why the CMRR tends to infinity for a symmetric ckt when emitter resistance becomes infinity(nov-2011) 17. Explain (i) Bandgap reference (ii) Methods of improving slew rate 18. Draw the circuit of a simple bipolar transistor current source and show that its output current is dependent upon of the transistor. Explain how the circuit can be modified to be less insensitive to. 19. Draw the circuit of a differential amplifier with current mirror load. Draw its equivalent circuit and derive its gain. 20. What is a current mirror? Discuss in detail the operation of current mirror and sketch improved circuit.(nov-2012). 21. Explain slew rate.what is fill power bandwidth?and also explain the methods to improve slew rate?.(nov-2012,apr-2011,apr-2010). 22. Define offset voltage.explain methods to nullify off-set voltage.(nov-2012,apr- 2011) UNIT-II PART-A 1. What is a zero crossing detector? 2. Give any four applications of a comparator. 3. What is a voltage follower? (Apr-2014) 4. What is the need for an instrumentation amplifier? 5. State the requirements of instrumentation amplifier. (Apr-2013,Apr-2011) 6. What are the applications of V-I converter? 7. Draw the circuit diagram of I-V converter?(apr-2010) 8. Give an application of an inverting amplifier. (Apr-2013) 9. What do you mean by a precision rectifier?differentiate with conventional rectifier(nov 2012,Apr-2011,Nov-2014) 10. Write down the applications of precision diode. 11. List the applications of Log amplifiers: 12. What are the limitations of the basic differentiator circuit? 13. Write down the condition for good differentiation and draw the circuit.(nov- 2012,Apr-2010). 14. What is a comparator?(may-2012,nov-2012) 15. Why active guard is necessary for instrumentation amplifier?(may-2012) 16. What are the applications of comparator? 17. What is a Schmitt trigger? 18. What do you understand by an Integrator? (Apr-2013,Nov-2010) 19. What are the characteristics of a comparator?

4 20. What is a filter? 21. What are the demerits of passive filters? 22. What are the advantages of active filters? 23. Mention some commonly used active filters : 24. What is the most important application of a Schmitt trigger circuit? 25. What are the different types of filters? 26. What are the requirements for producing sustained oscillations in feedback circuits? 27. Define conversion time. 28. What is a window detector? 29. What is hysteresis? What parameter determines the hysteresis? 30. List the types of comparators 31. State the conditions for oscillations 32. Differentiate Schmitt trigger and comparator 33. Draw the circuit of practical integrator. 34. Draw the circuit of practical differentiator. 35. What are the limitations of an ideal active differentiator? 36. Why integrators are preferred over differentiator?(nov-2011) 37. Using an op-amp draw the circuit diagram of a phase shift oscillator. 38. Draw a precision HWR. 39. What do you understand by instrumentation amplifier?(apr-2013) 40. How does the precision rectifier differ from the conventional rectifier? 41. What are the advantages of active filters over the passive filters? 42. With neat diagram, explain the application of op-amp as precision rectifier, clipper and clamper.(apr-2014) 43. Draw the freq. response of the LPF, HPF, and BPF & BSF. 44. What is AC amplifier? 45. What is Trans-conductance amplifier? 46. What is clipper? Mention its types. 47. What is clamper? Mention its types. 48. Draw the circuit diagram of Peak Detector. (Apr-2014) 49. What is log amplifier? Draw the circuit of a basic log amplifier. 50. Draw the circuit of differentiator and write the expression for the output voltage Vo. 51. Draw the circuit of integrator and write the expression for the output voltage Vo 52. What do you mean by programmable Trans Conductance amplifier? Mention its applications 53. Draw the characteristics of an ideal comparator and practical comparator. 54. Draw an op-amp circuit for converting a square wave into a series of positive pulses. 55. What is a Schmitt trigger? Why is it called as regenerative comparator? 56. Define VUT, VLT and Hysteresis in Schmitt trigger. 57. Define Bandwidth of a filter(nov-2014) PART-B 1. How is a log amplifier realized with an opamp?

5 2. Explain the following applications of opamp(nov-2010,may-2012)) i. Peak detector ii. V/I converter(floating load & Grounded load) iii.multiplier iv.scale changer v.inverter 3. Design a second order active high pass filter for a cutoff frequency of 5KHZ 4. Design a second order active Low pass filter for a cutoff frequency of 5KHZ(Nov-2011,Apr-2010) 5. With neat diagram, explain logarithmic amplifier and antilogarithmic amplifier.(apr-2014,nov-2012,may-2011) 6. With a neat diagram, explain the operation of Schmitt trigger.(nov-2010,may- 2012,Nov-2011)) 7. Draw the circuit of differentiator and write the expression for the output voltage Vo.and also explain practical Differentiator(May-2012) 8. Draw and explain an ideal active op-amp Diffentiator circuit(apr-2010) 9. (a)draw and explain an ideal active op-amp integrator circuit(apr-2013) (b)draw the I/O waveforms for integrator (i) Step i/p signal (ii) Square wave input signal (iii) Sine wave input signal (c) Derive the expression for change in output voltage. (d) List the applications of practical integrator. (e) Design a practical integrator circuit with a dc gain of 10, to integrate a square wave of 10 KHz. 10. Draw the circuit diagram and explain the working of an instrumentation amplifier. Mention the specific advantages of three op-amp instrumentation amplifier circuit. (Apr-2013,Nov-2011,Nov-2014) 11. Draw the circuit diagram and explain the working of an Adder-Subtractor (or)draw a circuit to find VO= (V1+V2)-(V3+V4) (Nov-2011,Apr-2010). 12. Explain Positive clipper using opamp.(apr-2010). 13. Explain Precision Full wave Rectifier using opamp.(nov-2014). 14. Draw the circuit of a first order and second order butter worth active low pass filter and derive its transfer functions. 15. Design a fourth order Butterworth LPF having a upper cutoff frequency of 1 KHz.(May-2012) 16. Design a square wave oscillator for f0 = 1 KHz using 741 op-amp and a DC supply voltage of +/-12V. 17. Design an Opamp Schmitt trigger with VUT= 2V, VLT= -4V & the output swings b/w +10V. If the i/p is 5 sin wt, plot i/p & o/p waveforms. 18. Explain the applications of comparator. 19. Explain the following applications of opamp(nov-2010,nov-2011,may-2011)) i. Scale changer ii. Voltage follower iii.non inverting adder iv.integrator

6 17. Explain the steps involved in the design of a band pass filter using OPAMP.(Nov-2010) UNIT-III PART-A 1. Mention the application of analog multiplier. 2. Draw the block diagram of PLL as frequency multiplier 3. What is PLL? 4. Draw a basic block diagram of PLL. 5. What is VCO?(Apr-2010) 6. VCO is called as V-F converter.why?(may-2012) 7. VCO is called as V-F converter.define V-F conversion factor Kv(Apr-2011) 8. A PLL frequency multiplier has an input frequency of f and a decade counter is introduced in the loop. What will be the frequency of the PLL output? (Apr-2013) 9. State the operation of a basic PLL. (Apr-2014) 10. Define lock range, Capture range and pull-in time in PLL?(Nov-2010,Nov- 2011,Nov-2012,Apr-2010) 11. How does a PLL track the incoming frequency? 12. What is the need for frequency synthesizer? (Apr-2014) 13. Mention any two applications of PLL. (Apr-2013) 14. What is 2-Quadrant Multiplier?(Nov-2012) 15. State the advantages of variable transconductance technique for analog multiplication.(nov-2011) 16. State the advantages of emitter coupled transistor pair.(apr-2011). 17. What is the need for Phase detector in PLL(Nov-2014) PART-B 1. Explain the applications of analog multiplier(apr-2011) (i)squaring (ii)square rooting (iii)frequency doubler (iv)phase angle detector 2. Explain the functional block diagram of PLL IC A PLL is locked on to an incoming signal with a frequency of 1MHz at a phase angle of 50 deg. The VCO signal is at a phase angle of 20 deg. The peak amplitude of the incoming signal is 0.5V and that of the VCO output signal is 0.7V. a. What is VCO frequency? b. What is the value of the control voltage being feedback to the VCO at this point? 4. Explain the application of PLL as AM detector, FM Detection and FSK demodulation. (Apr-2014,Apr-2011)

7 5. Explain the working of Analog multiplier using emitter coupled transistor pair. Discuss the applications of Analog multiplier IC. (Apr-2014,Nov-2011,Nov-2014) 6. Draw the circuit of a frequency multiplier/divider using PLL & explain its operation. 7. (a)what do you mean by variable transconductance analog multiplier? (b) State the advantages of variable transconductance technique for analog multiplication. (c) Draw the circuit and explain the working of one quadrant variable transconductance analog multiplier. (Apr-2013,Nov-2012,Apr-2010) 8. What is PLL? Draw the block schematic of PLL and explain its operation. (Apr-2010) 9. What is VCO? What is the purpose of VCO? Draw the block diagram and connection diagram of IC 566 VCO and explain. Obtain an expression for frequency of oscillation.(nov-2010,apr-2010) 10. Draw the block diagram and explain the principle of working, characteristics and applications of a. Frequency synthesizer b. FSK demodulator c. AM Detector d. FM detector (Apr-2013,May-2012,Nov-2011,Apr-2011,Nov-2014) 11. In the connection diagram of VCO shown below, +V = 12V, R2 = 1.5KO, R1=R3=10KO and C1=0.001F, a. Determine the nominal frequency of output waveform b. Compute the modulation frequency in the output frequency if control voltage is varied between 9.5V and 11.5V. 12. Discuss the applications of Analog multiplier IC as a Divider circuit and Frequency doubler.and also list the performance parameters of a Multiplier IC(Nov-2012,May-2012) 13.Draw the functional block schematic of a NE565 PLL and explain the roles of the low pass filter and VCO. Derive the expression for the capture range and lock in range of the PLL(Nov-2010,Nov-2011,) UNIT-IV PART-A 1. What is the function of DAC and ADC? 2. Classify DACs. 3. Classify ADCs. 4. Name the essential parts of a DAC. 5. Why is an inverted R-2R ladder network DAC better than R-2R ladder DAC? 6. Which is the fastest ADC and why?(nov-2011) 7. Draw the symbol of n bit D/A converter. What is the number of different output levels that can be produced by a given DAC? 8. Define resolution of a DAC.(Nov-2011,Nov-2014)) 9. Discuss the disadvantages of integrating type ADC.(Apr-2010) 10. Draw the symbol for an n-bit A/D converter.

8 11. Define FSR of A/D converter. 12. Draw the transfer characteristics of an ideal 4 bit A/D converter and explain. 13. Define Accuracy of A/D converters.(apr-2011) 14 Which is the fastest ADC? Give reason (Apr-2011) 15. What is a sample/hold circuit? (Apr-2014,Nov-2014) 16. Give two advantages of SA type ADC. 17. Mention any two specifications of a D/A converter. (Apr-2013) 18. For an n-bit flash type A/D converter, how many comparators are required? State the disadvantage of that type of converter(apr-2013) 19. Compare and contrast binary ladder and R-2R ladder DAC?(Nov-2010) 20.Define resolution and conversion time of DAC.(Nov-2010,Apr-2010) 21.what output would be produced by a D/A converter whose output is 0 to 10V and whose input binary is 0110 for a 4bit DAC..(Nov-2012) 22.What is the drawback of Dual slope ADC?(Nov-2012,May-2012) 23. Define Settling time of DAC.(May-2012) PART-B 1.A 4-bit DAC has VFS = 10V. Determine Vo, given the following binary inputs. a b c d For the 4-bit weighted resistor DAC shown below, R=80 KΩ and RF=8 KΩ. Assuming that VREF = -5V, determine the LSB size, VO(max) and VFS. 3.The R-2R ladder DAC shown below consists of 10KΩ & 20KΩ resistors, VREF = 2V and R1 = 10KΩ. Determine the values required for RF such that VFS = 10V. 4.With a neat sketch, explain Flash type ADC(Nov-2011). 5.With a neat block diagram, explain oversampling ADC(Nov-2012,Apr-2011). 6.Explain (i)totem pole MOSFET switch 2)CMOS inverter as a switch used in DAC(May-2012) 7. Draw the block diagram and explain the working of (Apr-2013) (i) Charge balancing VFCS (ii) Voltage to Time Converter 8.Explain weighted resistor type and R-2R ladder type DAC,Inverter R-2R Ladder DAC. (Apr-2014,Nov-2012,May-2012,Nov-2011,Apr-2011,Apr- 2010,Nov-2014) 9.With a neat sketch, explain successive approximation ADC.(Nov-2010,Nov- 2012,Apr-2011,Apr-2010) 10. Explain flash type. single type and Dual slope type ADC. (Apr-2014,May-2012) 11. With a neat sketch, explain dual slope ADC(Apr-2013) 12. Compare single slope ADC and dual slope ADC(Apr-2013,Nov-2010May- 2012) 13. For a particular dual slope ADC, t1 is ms and the reference voltage is 100 mv. Calculate t2 if (Apr-2013,Apr-2010) (i) V1 is 100 mv and (ii) 200 mv 14. Discuss the operation of sample and hold circuit with circuit diagram

9 (Nov-2010,Apr-2010) 15. With a neat sketch, explain Flash type ADC(Nov-2014) UNIT-V PART-A 1. What is the function of regulator? 2. What are the 2 types of regulators & how they differ in their operation? 3. What is meant by line regulation & load regulation of a voltage regulator?(nov-2014) 4. The input of a certain regulator increases by 3.5V. As a result, the output voltage increases by 0.42V. The nominal output is 20V. Determine the line regulation in %V. 5. A regulator has a no-load output voltage of 18V and a full-load output voltage of 17.8V at a load current of 50mA. Determine voltage regulation. 6. Why series regulators are called linear voltage regulators? 7. What are the basic components in a series regulator? 8. How does the control element in shunt regulator differ from that in series regulator? 9. What is the function of series pass transistor in series op-amp regulator? 10. What are the limitations of linear voltage regulator? 11. What are 3 terminal regulators? List its characteristics. 12. Sketch the basic circuit and write limitation of a 723 IC regulator.(nov-2012) 13. What are the three terminals of a fixed voltage regulator and an adjustable voltage regulator? 14. What is the output of each of the following IC regulators? a b c d What are the external components required for a basic LM317 configuration? 16. What are the limitations of 3 terminal IC regulators? 17. What is the purpose of using an external pass transistor with an IC voltage regulator? 18. What is meant by drop-out voltage of IC voltage regulator? 19. What are the built in protection arrangement present in an IC 723 voltage regulator?(dec-2014) 20. What is the advantage of current limiting in a voltage regulator? 21. How can a 3-terminal voltage regulator IC circuit modified to provide variable voltage o/p? 22. What is switching regulator? What is the primary advantage of switching regulator over linear regulator? 30. What must the relationship be between the pulse width tp and the period T of the input trigger signal if 555 Timer is to be used as a divide-by-4 network? 31. List two application each in which the 555 Timer can be used as a astable and monostable multivibrator.

10 32. What is the free-running frequency of oscillation of the 555 timer wired as an astable multivibrator? 33. What is a multivibrator? 34. What do you mean by monostable multivibrator? 35. What is an astable multivibrator? 36. What is a bistable multivibrator? 37. What are the requirements for producing sustained oscillations in feedback circuits? 38.Mention any two audio frequency oscillators : 39. Define duty cycle of a periodic pulse waveform when 555 Timer is configured as an astable multivibrator, how is the duty cycle determined?(nov-2011,may-2011) 40. Give the Time period for monostable multivibrator & astable multivibrator. 41. For a square wave oscillator calculate the frequency of oscillation if R2=10kΩ, R1=8.6kΩ, Rf= 100kΩ &C= 0.01µF. 42. What is a Multivibrator? 43. Draw the circuit of an astable multivibrator using op-amp. 44. What is the frequency of oscillation of an astable multivibrator? 45. Explain how a non symmetrical square wave can be obtained? 46. How do we convert a free running multivibrator to operate as a monostable multivibrator? 47. Using block schematic, Show a way of realizing a triangular wave generator from astable multivibrator. 48. Draw the circuit diagram of triangular wave generator and give the expression for its frequency of oscillation. 49. Give the formula for period of oscillations in an op-amp astable circuit. (Apr-2013) 50. Define duty cycle of a periodic pulse waveform. (Apr-2013) 51. What is an opto-coupler? (Apr-2014,Apr-2011) 52. Sketch the monostable multivibrator circuit diagram using 1C555.(Nov-2010) 53. What is meant by thermal shutdown applied to voltage regulators?(nov-2010) 54. What is power amplifier?(nov-2012,apr-2010) 55. What is a switched capacitor filter and its advantages?(may-2012,nov-2011) 56. What are the limitations of 3-terminal voltage regulator?(may-2012) 57. What are the waveforms generated buy ICL8038?(Apr-2010) PART-B 1. With a neat diagram, explain IC723 general purpose regulator. (Apr-2014,May-2012) 2. Write short notes on protective circuits in regulators 3. Explain series op-amp regulator with diagram. 4. Explain fixed voltage series regulator with its characteristics.(apr-2010) 5. Explain the current limit protection of 723 general purpose regulators. 6. Explain step down switching regulator in detail.(nov 2012,Apr-2011,Nov-2014) 7. Draw & explain the functional diagram of 555 timers.(may-2012) 8. With neat sketches of circuit diagram and waveforms, explain the operation of 555 Timer wired as an astable multivibrator.(nov-2011,apr-2010) 9. With neat sketches of circuit diagram and waveforms, explain the operation of 555 Timer wired as a monostable multivibrator. 10. With neat sketches of circuit diagram and waveforms, explain the operation of 555

11 Timer wired as a Schmitt trigger. 11. Draw the circuit of one-shot using a 555 Timer to provide one time period of 20?s. If RA = 7.5KΩ, what value of C needed? 12. Sketch the circuit of a 555 Timer connected as an astable multivibrator for operation at 350KHz.Dtermine the value of capacitance C needed using RA=RB=7.5KΩ. (5 Marks) 13. Discuss any 2 applications of monostable multivibrator using 555 Timer in detail. 14. Draw and explain the circuit of Schmitt trigger using 555 timers. 15. Explain functional diagram of 723 general purpose regulators. 16.What are the requirements for producing sustained oscillations in feedback circuits?discuss any two audio frequency oscillators. 17.Discuss in detail the working of a RC phase shift oscillator. 18.Discuss in detail the working of Isolation amplifier(may-2012) 19.Design Wien Bridge oscillator of 1 KHz frequency. 20.Draw and explain the operation of astable multivibrator using opamp and derive an expression for its frequency of oscillation.(nov-2014) 21.State the advantages of IC voltage regulator. Explain the features and internal structure of general purpose Linear IC723 regulator. Design a regulator using IC 723 to meet the following specifications: V0=5V, I0=100mA, Vin=15±20%, Isc=150 ma, Vsense=0.7V (Apr-2013) 22.Explain working of monostable multivibrator with necessary waveforms and derive an expression for its pulse width. 23.Draw and explain the operation of a triangular wave generator and derive an expression for its frequency of oscillation.(nov-2012,apr-2011) 24.Explain the working of a saw tooth waveform generator. Explain the methods to obtain asymmetric square wave. 25.Write detailed notes on the following: Low noise op-amps (ii) Integrated fiber optic system (Apr-2013) 26.Explain the working of optocuplers(may-2012,apr-2010). 27.Explain in detail voltage to frequency and frequency to voltage converters,video amplifier. (Apr-2014,Nov-2012,Apr-2011) 28.What is a switched capacitor filter and its advantages and disadvantages?(nov- 2011Apr-2011)