Fastest ADC architecture: Among common converter types, which analog-to-digital converter is known for the highest conversion speed (lowest latency) at a given resolution?

Introduction / Context:
ADC architectures trade off speed, power, area, and accuracy. In time-critical applications like high-speed oscilloscopes, radar front-ends, and communication receivers, the fastest conversion method is often required, even at the cost of power and silicon area.

Given Data / Assumptions:

• Compare counter-ramp, SAR, dual-slope, and parallel (flash) ADCs.
• Resolution is moderate (a few to ~8 bits typical for flash).
• Focus on raw conversion latency per sample.

Concept / Approach:
A parallel (flash) ADC uses 2^N − 1 comparators in parallel to compare the input simultaneously against all threshold levels generated by a resistor ladder. A priority encoder then converts the thermometer code to binary in essentially one comparator delay plus small logic latency. No sequential steps are required, making it the fastest architecture in terms of latency.

Step-by-Step Solution:

Verification / Alternative check:
Flash ADC datasheets specify sub-nanosecond to low-nanosecond latencies. SAR devices require N serial decisions; counter-ramp counts through many steps; dual-slope integrates over relatively long windows for precision and noise rejection.

Why Other Options Are Wrong:

• Counter ADC: Slow, sequential counting.
• Successive-approximation: Fast and popular, but still N serial steps.
• Dual slope: Precision over speed; conversion time is longest.

Common Pitfalls:
Equating throughput with latency without considering pipeline effects; overlooking power and area penalties of flash ADCs as resolution grows.

Final Answer:
parallel ADC