Flash (simultaneous) ADC timing What is the effective conversion time characteristic of a flash analog-to-digital converter?

Introduction / Context:
ADC architectures trade hardware complexity for speed. Flash ADCs are the fastest because they compare the input simultaneously against many thresholds.

Given Data / Assumptions:

• Flash ADC (aka simultaneous, parallel) with a resistor ladder and bank of comparators.
• No pipeline or sequential steps are involved in the basic decision.

Concept / Approach:
In a flash ADC, all comparator decisions occur in parallel, so the output code reflects the input essentially continuously, changing as soon as the comparators and encoder settle (propagation delay on the order of nanoseconds for many devices). Hence, there is no distinct multi-microsecond “conversion time” like in SAR or integrating ADCs.

Step-by-Step Solution:

Verification / Alternative check:
Datasheets specify propagation delay and maximum sampling rate; there is no N-cycle conversion sequence as in SAR.

Why Other Options Are Wrong:

• Fixed microsecond values: Those are characteristic of slower architectures and are orders of magnitude longer than flash delays.

Common Pitfalls:

• Confusing sampling period (set by external clock) with internal conversion latency; flash conversion is parallel.

Final Answer:
The conversion takes place continuously.