AD/DA conversion
Which is a characteristic of a flash AD converter?
- AIt converts in one step using many comparators in parallel, so it is fast, but circuit size grows rapidly with resolution
- BIt compares one bit at a time, so it is slow but small
- CIt integrates the input voltage for a long time, so it is accurate but slow
Show answer and explanation
Answer: A. It converts in one step using many comparators in parallel, so it is fast, but circuit size grows rapidly with resolution
A flash converter compares the input voltage with reference voltages using 2ᴺ−1 comparators at once, so conversion finishes in a single comparison, making it the fastest architecture. In return, N bits require 2ᴺ−1 comparators, so area and power increase sharply as resolution increases.