Analysis and Design of Regenerative Comparators for Low Offset and Noise

We make the case that in most comparators, offset and noise are determined by a dynamic preamplifier always embedded ahead of a regenerative latch. An analysis of this amplifier follows, from which simple expressions are obtained for input-referred offset and noise bandwidth. Practical circuit methods to compensate offset and lower noise become evident. We compare the StrongArm comparator with the double tail topology, and identify requirements for correct operation.