# Linear Integrated Circuit Questions and Answers – A to D Converter – 1

This set of Linear Integrated Circuit Multiple Choice Questions & Answers (MCQs) focuses on ” A to D Converter -1″.

1. How many control lines are present in analog to digital converter in addition to reference voltage?
a) Three
b) Two
c) One
d) None of the mentioned

1. Start input-tell ADC when to start conversion.
2. EOC- end of conversion.

2. Find out the integrating type analog to digital converter?
a) Flash type converter
b) Tracking converter
c) Counter type converter

Explanation: Other than dual slope ADC the rest belongs to direct type ADCs.

c) Both integrating and direct type ADC
d) None of the mentioned

Explanation: Integrating type ADC performs conversion in an indirect manner by first changing the analog input signal to a linear function of time or frequency and then to a digital code.

4. Which A/D converter is considered to be simplest, fastest and most expensive?
a) Servo converter
d) All of the mentioned

Explanation: The simplest possible A/D converter is flash type converter and is expensive for high degree of accuracy.

5. The flash type A/D converters are called as
a) Parallel non-inverting A/D converter
b) Parallel counter A/D converter
c) Parallel inverting A/D converter
d) Parallel comparator A/D converter

Explanation: The flash type A/D converter are also called as parallel comparator A/D converter because the purpose of the circuit is to compare the analog input voltage with each node voltage.

6. What is the advantage of using flash type A/D converter?
a) High speed conversion
b) Low speed conversion
c) Nominal speed conversion
d) None of the mentioned

Explanation: Flash type ADC has the advantage of high speed as the conversion takes place simultaneously rather than sequentially. Typical conversion time is 100nanosecond or less.

7. The number of comparator required for flash type A/D converter
a) Triples for each added bit
b) Reduce by half for each added bit
c) Double for each added bit
d) Doubles exponentially for each added bit

Explanation: The number of comparator required almost doubles for each added bit. For example – 2 -bit ADC requires three comparators, 3 -bit ADC needs seven comparators and a 4 -bit ADC requires fifteen comparators.

8. Drawback of counter type A/D converter
a) Counter clears automatically
b) More complex
c) High conversion time
d) Low speed

Explanation: In counter type ADC counter frequency is kept low enough to give sufficient time for DAC to settle and for the comparator for respond. So, low speed is the most serious drawback.

9. Calculate the conversion time of a 12-bit counter type ADC with 1MHz clock frequent to convert a full scale input?
a) 4.095 µs
b) 4.095ms
c) 4.095s
d) None of the mentioned

Explanation: conversion time = 2n -1 clock periods = (12n-1) = 4.095ms.

10. In a servo tracking A/D converter, the input voltage is greater than the DAC output signal at this condition
a) The counter count up
b) The counter count down
c) The counter back and forth
d) None of the mentioned

Explanation: In servo converter, the circuit consist of an up/down counter with comparator controlling direction of the count. So, if the input voltage is greater than DAC output signal, the output of comparator goes high and counter is caused to count up.

11. At what condition error occurs in the servo tracking A/D Converter?
a) Slow change input
b) Rapid change in input
c) No change in input
d) All of the mentioned

Explanation: As long as the analog input changes slowly, the tracking A/D converter will be within one LSB of the corrected value. When the input changes rapidly, the tracking A/D converter cannot keep up with change and error occurs.

12. How many clock pulses do a successive approximation converter requires for obtaining a digital output.
a) Twelve
b) Six
c) Eight
d) None of the mentioned

Explanation: The successive approximation technique uses a very efficient code search strategy to compute n-bit conversion in just n-clock period.

Sanfoundry Global Education & Learning Series – Linear Integrated Circuits.

To practice all areas of Linear Integrated Circuits, here is complete set of 1000+ Multiple Choice Questions and Answers. 