What the MAX990ESA+ is and where it fits
The Maxim Integrated MAX990ESA+ is a dual, general-purpose comparator in an 8-SOIC package. It's designed for applications that need two independent voltage comparisons with fast response and minimal power draw. Typical uses include threshold detection, zero-crossing detectors, window comparators, and signal conditioning in battery-operated instruments, portable devices, and industrial control systems.
Key specs and what they mean for your BOM
The 450ns propagation delay (max) is fast enough for many control-loop and signal-conditioning tasks, though not intended for high-speed data conversion or RF-level switching. The 24µA quiescent current per comparator makes this a strong candidate for always-on monitoring circuits where every microamp counts. Input bias current is a mere 1pA at 5.5V, which means it won't load down high-impedance sources like pH probes, photodiode amplifiers, or capacitive sensors. The 5mV max input offset voltage is typical for a general-purpose comparator; if you need sub-millivolt precision, you'll want to look at a precision comparator family. The ±3mV hysteresis is built in, so you don't need external positive feedback for clean switching on slow edges. With 80dB CMRR and 80dB PSRR, this part rejects common-mode noise and supply ripple well enough for most industrial and portable environments. The output can drive CMOS, TTL, or open-drain loads and swings rail-to-rail, simplifying interface logic.
Lifecycle and compliance
The MAX990ESA+ is listed as Active and ROHS3 compliant. No end-of-life notice or last-time-buy window is in effect.