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QUESTION PAPERS
LINEAR INTEGRATED CIRCUITS (New) EC 305 5th Sem May 2k5
Note: Section A is compulsory. Attempt any Four questions from
section B and two from Section C.
Section A Marks 2 each
1.
(a) Explain the difference between constant current bias and current mirror.
(b) What is the difference between a basic comparator and Schmitt trigger?
(c) Explain the difference between digital and linear ICs.
(d) Show how a non-inverting amplifier can be made to operate as voltage
follower.
(e) Define input offset voltage and CMRR for an OP-AMP.
(f) What are advantages of adjustable voltage regulator over fixed voltage
regulator?
(g) Define break frequency and bandwidth.
(h) Explain the difference between integrator and differentiator and give one
application of each.
(i) What is VCO? Give tow applications that require VCO.
(j) What is voltage limiting and why is it needed?
Section B Marks 5 each
2. An emitter based dual input, balanced output differential amplifier has the
following specifications: Vcc = -VEE = 10 V. R¬c1=Rc¬2 = 2.7 kilo ohm and RE=
3.9 kilo ohm, ?ac=?dc=100, VBE = 0.715 V. Calculate:
(a) Operating current and voltage for each transistor.
(b) Voltage gain
3. Define all parameters that are used to specify an OP-AMP. List their
significance.
4. Draw block diagram of IC555 and explain its working.
5. Give a theoretical method to obtain the frequency curve of an operational
amplifier if the poles and zeros are not given.
6. In a triangular wave generator R2=1.2 kilo ohm,R3=6.8 kilo ohm, R1 = 120 kilo
ohm, c1=0.01 micro f.
Determine:
(a) Peak to peak output amplitude of triangular wave.
(b)Frequency of triangular wave.
Section C Marks 10 each
7. What is PLL? Explain its operating principle with the help of a block
diagram. Describe the function of each block in detail in block diagram. Discuss
at least tow applications of PLL. 1,2,3,4
8. (a) What are switching regulators? Describe theory of switching regulators.
(b) An on-inverting zero crossing detector uses OP-AMP micro A with an open loop
gain of 92 dB. If the power supply voltage are + 15 V and input offset 0 V:
(i) find the input voltage range that causes the output voltage to slew between
the power supply rates.
(ii) if a 1 mV sin wave is on the input, draw the output waveform in time
synchronization with input waveform.
9 (a) An inverting voltage comparator uses an OP-AMP with saturation voltages of
+ 12 V, R1=2 k ohm, RF=390 k ohm. The reference voltage is -3V. Determine two
voltages at which the comparator will switch.
(b) Describe differential mode Instrumentation Amplifier. Find its output.