ADC architectures — match each converter type to its hallmark requirement or benefit List I (ADC type) A. Flash converter ADC B. Dual-slope ADC C. Successive-approximation ADC List II (Characteristic) 1. Requires conversion time of only a few microseconds 2. Requires a DAC in its feedback path 3. Minimizes effect of power-supply interference 4. Requires complex hardware 5. Is a tracking ADC
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AA-2, B-3, C-4
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BA-4, B-3, C-2
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CA-5, B-4, C-3
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DA-1, B-2, C-5
Answer
Correct Answer: A-4, B-3, C-2
Explanation
Introduction / Context:Different ADC topologies trade speed, accuracy, complexity, and noise immunity. Pairing each with its defining trait enables informed converter selection for embedded and instrumentation systems.
Given Data / Assumptions:
- Flash ADC: parallel comparators and a resistor ladder.
- Dual-slope ADC: integrates input then reference, excellent at rejecting line hum.
- SAR ADC: binary search using DAC + comparator under SAR logic.
Concept / Approach:Flash converters are the fastest but require many comparators → complex hardware. Dual-slope inherently averages the signal over an integer number of mains cycles → strong power-supply hum rejection. SAR uses an internal DAC to refine the trial code each bit time → requires DAC in its feedback path.
Step-by-Step Solution:
A (Flash) → 4 (requires complex hardware).B (Dual-slope) → 3 (minimizes power-supply interference).C (SAR) → 2 (requires DAC in feedback).Verification / Alternative check:Compare converter block diagrams: flash shows N-bit wide comparator array; SAR blocks include DAC; dual-slope timing diagrams integrate over T_int and T_ref to cancel periodic interference.
Why Other Options Are Wrong:
- “Tracking ADC” describes a different architecture (up/down counter type), not SAR or flash.
- Assigning “few microseconds” generically is ambiguous; many SARs are microseconds too, but the option set uses structural traits.
Common Pitfalls:Confusing dual-slope with delta-sigma; both integrate, but delta-sigma uses oversampling and noise-shaping.
Final Answer:A-4, B-3, C-2