What this comparator does on the board
The MAX987ESA+ is a single general-purpose comparator from Analog Devices, housed in an 8-SOIC package. It compares two analog voltages and outputs a digital high or low based on which input is higher, with a propagation delay of 210 ns max — fast enough for most control-loop and threshold-detection tasks in industrial and battery-powered gear.
Supply flexibility and power budget
Quiescent current maxes out at 96 µA, so it won't drain a battery in a sensor node that sleeps most of the time.
Noise immunity and signal integrity
Built-in hysteresis of ±2.5 mV prevents output chatter when the input signal rides on noise — a common headache in industrial environments with motor drives or switching supplies nearby. The 80 dB CMRR and 80 dB PSRR mean the comparator's threshold stays put even when the common-mode voltage drifts or the supply rail has ripple.
Input bias and offset — what they matter for
Input offset voltage is 5 mV max at 5.5 V, so the trip point is within 5 mV of the ideal; for precision thresholding, you may need to account for this in the resistor divider.