Single comparator with a built-in reference — what that buys you
The MAX921EPA+ is a single comparator from Maxim Integrated that packs its own voltage reference on-chip. That means you get a stable threshold without an external reference IC or resistor divider — one less component to source and place. The internal reference is trimmed, so the trip point holds across temperature and supply shifts. Typical applications include battery monitors, threshold detectors, and window comparators where board space is tight and the reference load is light. Quiescent current maxes out at 5 µA. The single supply range covers 2.5 V to 11 V, or split rails ±1.25 V to ±5.5 V.
12 µs propagation delay — what it means for the loop
The 12 µs max propagation delay sets the response speed for over-voltage or under-voltage detection. That is fine for line-frequency monitoring, battery charge termination, or slow sensor thresholds. It will not work for high-speed PWM current limiting or fast-switching power supply protection — those need a comparator in the sub-microsecond range. The 50 mV of built-in hysteresis cleans up the switching edge on a noisy rail and prevents chatter near the threshold.
Through-hole DIP — still the right call for lab, prototype, or high-reliability builds
The 8-pin DIP package (0.300" body, 7.62 mm pitch) is through-hole, not surface-mount. That makes it easy to hand-prototype, socket in a test fixture, or mount on a board that avoids SMD reflow for reliability reasons. The 8-PDIP supplier package code is the same footprint. Output is CMOS and TTL compatible, so it drives logic inputs directly without a pull-up resistor.
Lifecycle and compliance — no end-of-life surprises
The MAX921EPA+ carries an Active lifecycle status from the manufacturer. That means no last-time-buy clock ticking, no NRND flag. It is ROHS3 compliant, so it passes the current EU material restriction regime. For a BOM line that needs a through-hole comparator with an internal reference, this part is a safe long-term choice — no redesign pressure from obsolescence.
Sourcing — available through independent distribution
This part is sourced and quoted to order against an RFQ through our independent distribution network. Submit an RFQ for tube quantities as shipped from the factory.