Wednesday, 29 August 2012
LIC EC 2254 LINEAR INTEGRATED CIRCUITS ANNA UNIVERSITY PREVIOUS YEAR QUESTION PAPER-ANNA UNIVERSITY FOR 2 YEAR SEMESTER FOURTH SEMESTER ECE STUDENTS-EC 2254 LINEAR INTEGRATED CIRCUITS(LIC) ANNA UNIVERSITY PREVIOUS YEAR QUESTION PAPER-IMPORTANT QUESTIONS, 2 MARKS AND 16 MARKS QUESTIONS FOR ECE DEPARTMENT
EC2254 — LINEAR INTEGRATED CIRCUITS
PART A — (10 × 2 = 20 Marks)
1. What is an integrated circuit?
2. What is current mirror?
3. Give the schematic of op-amp based current to voltage converter.
4. Draw the circuit diagram of differentiator and give its output equation.
5. What is a VCO?
6. Draw the relation between the capture ranges and lock range in a PLL.
7. Define resolution of a data converter.
8. Give the advantages of integrating type ADC.
9. Draw the internal circuit for audio power amplifier.
10. What are the three different wave forms generated by ICL8038?
PART B — (5 × 16 = 80 Marks)
11. (a) (i) Define CMRR. Draw the circuit of an Op-amp differential amplifier
and give the expression for CMRR. (8)
(ii) Define Slew Rate. Explain the cause of slew rate and derive an
expression for Slew rate for an op-amp voltage follower. (8)
(b) Briefly explain the various processes involved in fabricating monolithic
IC which integrates bipolar transistor, diode, capacitor and resistor. (16)
12. (a) (i) Design a first order Low-pass filter for cut-off frequency of 2 KHz
and pass-band gain of 2. (8)
(ii) Explain a positive clipper circuit using an Op-amp and a diode with
neat diagrams. (8)
(b) (i) Design a circuit to implement 2 1 4 3 0 2 25 . 1 273 . 0 545 . 0 V V V V V − − + = .
(ii) Draw and explain a simple Op-amp differentiator. Mention its
limitations. Explain with a neat diagram how it can be overcome in
a practical differentiator. Design an Op-amp differentiator that will
differentiate an input signal with maximum frequency
Hz 100 fmax = . (8)
13. (a) (i) With a neat diagram explain the variable transconductance
technique in analog multiplier and give its output equation. (8)
(ii) Briefly explain the working of voltage controlled oscillator. (8)
(b) What are important building block of phase locked loop ( PLL) explain its
14. (a) (i) Explain the working of R-2R ladder DAC. (8)
(ii) Explain the working of success approximation ADC. (8)
(b) (i) A dual slope ABC uses a 16-bit counter and a 4 MHz clock rate. The
maximum input voltage is +10V. The maximum integrator output
voltage should be -8V when the counter has recycled through
n 2 counts. The capacitor used in the integrator is F µ 1 . 0 . Find the
value of resistor R of the integrator. (8)
(ii) What is a sample and hold circuit? Briefly explain its construction
and application. (8)
15. (a) (i) How is voltage regulators classified? Explain a series voltage
(ii) What is an optocoupler? Briefly explain its characteristics. (8)
(b) With a neat circuit diagram and internal functional diagram explain the
working of 555 timers in astable mode. (16)