Analog Devices Inc./Maxim Integrated MAX981EPA+

Overview

MAX981EPA+ from Maxim Integrated is a single, ultra-low-power, open-drain comparator with integrated 1.182V ±2% bandgap reference and programmable hysteresis via HYST pin. It operates from 2.5V to 11V single supply (or ±1.25V to ±5.5V dual supply), draws ≤4µA over temperature, supports rail-to-rail input down to V− and within 1.3V of V+, and features separate GND for output stage-enabling bipolar-to-single-ended level translation in battery-powered threshold detection.

For engineers reviewing the MAX981EPA+ datasheet, MAX981EPA+ pinout, MAX981EPA+ application, or MAX981EPA+ equivalent, key selection considerations include its guaranteed −40°C to +85°C extended temperature range, 12µs propagation delay at 10mV overdrive, open-drain output with 11V swing referenced to V−, internal reference accuracy tolerance, and HYST pin hysteresis programming method using two external resistors.

Technical Context

The MAX981EPA+ integrates a micropower comparator core and a precision bandgap reference on a single die, with the reference voltage (1.182V ±2%) referenced to V−-not GND-enabling true dual-supply operation. Its HYST pin allows hysteresis configuration without feedback networks, delivering deterministic switching thresholds via resistor divider between REF and V−.

Input common-mode range extends from V− to (V+ − 1.3V); output uses an N-channel open-drain transistor sinking to GND (not V−), permitting level-shifting across isolated domains. Propagation delay is specified at 12µs (high-to-low) with 10mV overdrive and 100pF load, and supply current remains stable across 2.5V–11V operation.

Key Specifications

Pinout & Package

MAX981EPA+ is housed in an 8-pin plastic DIP package (0.300" width) with through-hole mounting and industry-standard pin spacing. Pin 1 is located at the left end of the top row when viewed from the top with notch or dot oriented left.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar comparator applications.

Compared with MAX971EPA+, MAX981EPA+ trades reference accuracy for broader tolerance margin and identical hysteresis implementation, while TLV3701CDR reduces current but increases component count and design complexity for threshold generation.

Availability

MAX981EPA+ is available at Aetrix Electronics and suitable for battery-powered systems, threshold detectors, and level translators requiring stable component supply across extended temperature environments and long production lifecycles.

Supply support for MAX981EPA+ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Maxim Integrated (now part of Analog Devices) designs precision analog and mixed-signal ICs for power, sensing, interface, and timing applications in industrial, automotive, and communications markets.

The MAX971–MAX984 comparator family was engineered for ultra-low-power, high-accuracy threshold detection in resource-constrained systems-emphasizing micropower operation, integrated references, and simplified hysteresis without external feedback.

FAQ

What is the maximum supply voltage for MAX981EPA+ in single-supply operation?

The MAX981EPA+ supports a single-supply voltage range of 2.5V to 11V. When operated with V− tied to GND, the total supply voltage (V+ − V−) must not exceed 11V. Absolute maximum ratings allow V+ up to 12V relative to V−, but functional operation is guaranteed only up to 11V per datasheet specifications. Exceeding 11V may compromise reliability or parametric performance.

Does MAX981EPA+ require an external pull-up resistor on the OUT pin?

Yes, MAX981EPA+ requires an external pull-up resistor on the OUT pin because it features an open-drain N-channel output stage. Without a pull-up, the output cannot drive a logic-high state. Typical values range from 10kΩ to 1MΩ depending on speed and load requirements; the datasheet specifies 1MΩ for propagation delay characterization. The pull-up voltage may be different from V+, enabling level translation functionality.

Can the internal reference of MAX981EPA+ be used to bias external circuitry?

Yes, the REF pin of MAX981EPA+ can source up to 25µA and sink up to 15µA while maintaining ±2% accuracy over temperature, making it suitable for biasing low-current external circuitry such as resistor dividers, small MOSFET gates, or additional comparators. However, the datasheet explicitly warns against bypassing REF with capacitors, as this may cause instability or increased noise.

How is hysteresis programmed on MAX981EPA+ using the HYST pin?

Hysteresis on MAX981EPA+ is programmed by connecting two resistors: R1 between REF and HYST, and R2 between HYST and V−. This creates a voltage divider that sets HYST to a value between REF − 50mV and REF, defining a hysteresis band of up to 100mV. The equations R1 = V_HB/I_REF and R2 = (1.182V − V_HB)/I_REF apply, with I_REF typically chosen between 0.1µA and 4µA to balance accuracy and power.

Is MAX981EPA+ pin-compatible with other devices in the MAX971–MAX984 family?

Yes, MAX981EPA+ shares identical 8-pin DIP pinout with MAX971EPA+, MAX972EPA+, MAX973EPA+, MAX982EPA+, and MAX983EPA+. All use the same pin assignments: Pin 1 = GND, Pin 2 = V−, Pin 3 = IN+, Pin 4 = IN−, Pin 5 = HYST, Pin 6 = REF, Pin 7 = V+, Pin 8 = OUT. This enables drop-in substitution where reference tolerance and hysteresis capability meet design requirements.