ANALOG INTEGRATED CIRCUITS (utu previous year question papers)

ANALOG INTEGRATED CIRCUITS
SEM-IV, 2011
B TECH QUESTION PAPER
UTTARAKHAND TECHNICAL UNIVERSITY
(UTU)

Time: 3 hours

Total marks: 100

Attempt any four of the following:

1. Draw and explain the working of Wilson current mirror circuit and its improved version.
2. Design a Widlar current source for operating a constant current I_o=10µA. Assume V_CC=10 V, V_BE= 0.7 V and β =125 (use V_T= 25 mV).
3. Draw and explain the circuit of a V_BE multiplier.
4. When does a current mirror circuit deviates from the ideal condition?
5. Why is cascade configuration used in an Op-amp? Are FET op-amp better than BJT?
6. Explain MOS current steering circuits in brief.

Attempt any four of the following:

1. Show with the help of a circuit diagram an op-amp used as
   (i) Scale changer and
   (ii) phase shifter.
2. Sketch the circuit of a push-pull Class B transistor amplifier in the common collector configuration
   (i) With an output transformer
   (ii) Without an output transformer
3. Describe the five point method of computing harmonic distortion. Explain why even harmonics are not present in a push-pull amplifier.
4. Draw the circuit of a current to voltage converter and explain its operation.
5. Sketch a sample and hold circuit using op-amp and explain its operation.
6. Differentiate between cross over and harmonics distortions.

Attempt any two of the following:

1. Define slew rate. What causes the slew rate? Is this a small signal limitation of any IC?
2. Classify filters. Design a 50 Hz active Notch filter.
3. What is an instrumentation amplifier? Draw a system whose gain is controlled by an adjustable resistance.

Attempt any two of the following:

1. Draw and explain the working of Log and Anti-log amplifier circuit.
2. Draw and explain the circuit of Astable multivibrator using BJT. How it can be modified to get a triangular wave generator?
3. Discuss the internal component of 555 timer circuit and explain its usage as astable multivibrator.

Write short note on any four of the following:

1. Draw the basic building block of PLL.
2. Define the following terms related to PLL:
   (i) Capture range
   (ii) Lock range and
   (iii) Pull-in time.
3. Draw the block diagram of a VCO circuit (IC 566).
4. Design a square wave oscillator using 741 IC for f_o= 1 kHz.
5. Design a second order Butterworth high pass filter having lower cut-off frequency f= 1 kHz.

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