What this comparator does on the board
The MAX903ESA+T is a single comparator with a built-in latch, meaning it holds the last output state after the strobe signal goes inactive — useful in zero-crossing detectors or window comparators where the decision must be frozen for the downstream logic to read. It operates from a single 5V to 10V supply or dual ±2.5V to ±5V rails, and its TTL output interfaces directly with 5V logic families without a level translator.
Key parametrics for the BOM line
Typical CMRR of 82.5 dB and PSRR of 80 dB mean the comparator rejects common-mode noise and supply ripple well — a 10 mV input offset at the trip point is not swamped by a 1 V ground bounce on the supply rail. Quiescent current max is 4 mA, 3 mA, or 1.5 mA depending on the supply configuration — the 1.5 mA figure applies to the single 5 V rail, keeping the power budget tight in a low-current sensor node.