Analog Devices Inc./Maxim Integrated MAX981ESA

Overview

The MAX981ESA from Maxim Integrated is a single, ultra-low-power, open-drain comparator with internal 1.182V ±2% voltage reference and programmable hysteresis via HYST pin. It operates from 2.5V to 11V single supply (or ±1.25V to ±5.5V dual), draws ≤4µA supply current over temperature, supports rail-to-rail input down to V− and within 1.3V of V+, and features separate GND pin for output stage-enabling bipolar-to-single-ended level translation in battery-powered threshold detection systems.

For engineers reviewing the MAX981ESA datasheet, MAX981ESA pinout, MAX981ESA application, or MAX981ESA equivalent, this page delivers verified technical context, exact pin functions, real-world use cases in low-voltage sensing, and validated alternative options for design continuity and supply resilience.

Technical Context

The MAX981ESA integrates a precision bandgap reference (1.182V ±2% over −40°C to +85°C) referenced to V−, not GND, and a single comparator with open-drain N-channel output sinking to GND. Its HYST pin enables hysteresis programming using two external resistors without feedback loops-reducing noise sensitivity while maintaining micropower operation.

Input common-mode range spans V− to (V+ − 1.3V); output voltage swing reaches up to 11V above V−, supporting level-shifting across incompatible logic domains. Propagation delay is 12µs (10mV overdrive, 100pF load, 1MΩ pullup), and input offset voltage is ±10mV max-critical for accurate low-overdrive threshold decisions in energy-constrained systems.

Key Specifications

Pinout & Package

MAX981ESA is supplied in an 8-pin SO (Small Outline) package, pin-compatible with industry-standard SOIC-8 footprint (JEDEC MS-012). The device uses a standard 8-pin DIP/SO/µMAX pinout configuration shared across the MAX971/MAX981 family.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX971ESA, MAX981ESA trades ±1% reference accuracy for cost efficiency while retaining identical hysteresis control, supply flexibility, and output architecture; TLV3701IDBVR offers lower quiescent current but lacks integrated reference-increasing component count and layout sensitivity in reference-dependent designs.

Availability

MAX981ESA is available at Aetrix Electronics and suitable for battery-powered systems, industrial level translators, window comparators, and oscillator circuits requiring stable component supply across extended temperature ranges.

Supply support for MAX981ESA 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, and interface applications in industrial, automotive, and communications markets.

The MAX971–MAX984 comparator family targets ultra-low-power, reference-integrated threshold detection-optimized for long-life battery operation, wide supply flexibility, and minimal external component count in space-constrained systems.

FAQ

What is the reference voltage tolerance of MAX981ESA over its full operating temperature range?

The MAX981ESA features a 1.182V internal bandgap reference with ±2% accuracy over the extended temperature range of −40°C to +85°C. This specification is guaranteed per the manufacturer's datasheet and applies to all MAX981ESA units shipped in the E-grade temperature version. The reference is referenced to V−, not GND, so proper grounding of V− is essential for accurate threshold setting in MAX981ESA designs.

Can MAX981ESA operate from a 1.8V single supply?

No, MAX981ESA cannot reliably operate from a 1.8V single supply. Its guaranteed minimum single-supply voltage is 2.5V. Below 2.5V, performance degrades: reference output becomes unstable below ~2.2V, and comparator propagation delay increases significantly. While the comparator core may function down to ~1V in some conditions, this is outside specification and unsupported-use MAX974/MAX984 for true low-voltage operation, or select a different comparator family for 1.8V systems.

How is hysteresis programmed on MAX981ESA, and what is the maximum hysteresis band achievable?

Hysteresis on MAX981ESA is programmed by connecting two resistors between REF, HYST, and V−. The HYST pin accepts voltages from REF down to (REF − 50mV), enabling a maximum hysteresis band (V_HB) of 100mV. For example, setting V_HYST = REF − 25mV yields V_HB ≈ 50mV. The equations R₁ = V_HB/I_REF and R₂ = (1.182V − V_HB)/I_REF determine resistor values, where I_REF is typically 0.1–4µA-ensuring compatibility with MAX981ESA's 25µA reference source capability.

Does MAX981ESA require an external bypass capacitor on the REF pin?

No, MAX981ESA does not require-and must not have-an external bypass capacitor on the REF pin. The datasheet explicitly warns against bypassing REF, as it destabilizes the internal bandgap reference and increases output noise. Instead, ensure low-impedance routing and avoid capacitive coupling from noisy signals (especially OUT) to REF. If supply noise is present, place a 100nF ceramic capacitor between V+ and V− near the MAX981ESA package, not on REF.

What is the maximum output sink current of MAX981ESA, and how does it vary with supply voltage?

MAX981ESA's open-drain output can sink up to 50mA continuously, as specified in absolute maximum ratings. However, practical sink current depends on V+: at V+ = 5V, typical sink current is 1.8mA at V_OL = 0.4V; at V+ = 3V, it drops to ~0.8mA under the same condition. The output MOSFET's gate drive comes from V+, so lower V+ directly reduces sink strength. For loads requiring >1mA at low V+, verify VOL in actual operating conditions using the "OUTPUT VOLTAGE LOW vs. LOAD CURRENT" curve in the MAX981ESA datasheet.