Analog Devices Inc./Maxim Integrated MAX981CUA+

Overview

The MAX981CUA+ from Maxim Integrated is a single, ultra-low-power, open-drain comparator with integrated 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 quiescent current 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 systems.

For engineers reviewing the MAX981CUA+ datasheet, MAX981CUA+ pinout, MAX981CUA+ application, or MAX981CUA+ equivalent, key selection criteria include its 4µA max supply current at +70°C, 12µs propagation delay (10mV overdrive), ±10mV input offset, 1.182V ±2% internal reference, and 8-pin µMAX package with dedicated GND and HYST terminals for hysteresis configuration without external feedback.

Technical Context

The MAX981CUA+ integrates a bandgap voltage reference referenced to V− (not GND) and a single comparator with open-drain N-channel MOSFET output sinking to GND. Its HYST pin enables precise hysteresis programming using two external resistors between REF and V−, producing a maximum 100mV hysteresis band without requiring positive feedback networks.

Input common-mode range spans V− to (V+ − 1.3V); output voltage swing reaches up to 11V above V− and remains functional even with no supply applied (V+ = V−). The device supports single-supply operation with V− tied to GND and maintains guaranteed performance across 0°C to +70°C.

Key Specifications

Pinout & Package

MAX981CUA+ uses an 8-pin µMAX package (3mm × 3mm, 0.5mm pitch), thermally enhanced with exposed pad. Pin 1 is OUT; Pin 2 is V−; Pin 3 is IN+; Pin 4 is IN−; Pin 5 is HYST; Pin 6 is REF; Pin 7 is V+; Pin 8 is GND. GND is isolated from V− to enable true bipolar-to-single-ended conversion.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX971CUA+, the MAX981CUA+ trades ±1% reference accuracy for broader commercial temperature tolerance and lower cost, while TLV3701IDBVR offers dramatically lower quiescent current but sacrifices internal reference and level-shifting capability - making MAX981CUA+ optimal for cost-sensitive, reference-integrated, bipolar-to-unipolar interface tasks.

Availability

MAX981CUA+ is available at Aetrix Electronics and suitable for battery-powered systems, threshold detectors, level translators, and oscillator circuits requiring stable component supply with long-term manufacturability and consistent parametric performance.

Supply support for MAX981CUA+ 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, medical, and consumer systems.

The MAX971–MAX984 comparator family was engineered for ultra-low-power, reference-integrated threshold detection in space- and energy-constrained portable electronics - emphasizing micropower operation, flexible supply ranges, and simplified hysteresis implementation.

FAQ

What is the reference voltage accuracy of the MAX981CUA+ over temperature?

The MAX981CUA+ features a 1.182V internal bandgap reference with ±2% accuracy over the 0°C to +70°C commercial temperature range. This tolerance is specified in the Electrical Characteristics table under "Reference Voltage" for MAX981–MAX984 devices. The reference is referenced to V−, not GND, and its output can source up to 25µA or sink up to 15µA while maintaining regulation.

Can the MAX981CUA+ operate from a 3V single supply?

Yes, the MAX981CUA+ fully supports 3V single-supply operation. Its specified supply range is 2.5V to 11V, and electrical characteristics-including 4µA max supply current, 12µs propagation delay, and ±10mV input offset-are guaranteed at 3V (V+ = 3V, V− = GND). Input common-mode range extends from GND to 1.7V, and the REF output remains stable at 1.182V ±2%.

How is hysteresis programmed on the MAX981CUA+?

Hysteresis on the MAX981CUA+ is programmed using the HYST pin (Pin 5) with two external resistors: R1 between REF (Pin 6) and HYST, and R2 between HYST and V− (Pin 2). The hysteresis band equals approximately twice the voltage difference between REF and HYST, adjustable from 0 to 100mV. No external feedback loop or op-amp is required - the internal architecture handles hysteresis generation directly.

Does the MAX981CUA+ have a push-pull or open-drain output?

The MAX981CUA+ has an open-drain N-channel MOSFET output (Pin 1). It sinks current to GND but cannot source current - requiring an external pull-up resistor to define the high-state voltage. This architecture enables wire-OR configurations, level shifting, and interface with higher-voltage logic families, and is explicitly confirmed in the General Description and Pin Description sections of the datasheet.

What is the purpose of the separate GND pin on the MAX981CUA+?

The separate GND pin (Pin 8) on the MAX981CUA+ isolates the output-stage ground from the signal ground (V−), allowing the output to sink current to a different reference potential. This enables bipolar-to-single-ended conversion - for example, accepting ±5V inputs while driving a 3.3V logic pull-up - and is essential for level-shifting applications where V− may be negative or floating relative to system GND.