Analog Devices Inc./Maxim Integrated MAX971CUA

Overview

The MAX971CUA from Maxim Integrated is a single, ultra-low-power, open-drain comparator with internal 1.182V ±1% 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.

For engineers reviewing the MAX971CUA datasheet, MAX971CUA pinout, MAX971CUA application, or MAX971CUA equivalent, key selection criteria include its 4µA max supply current at +70°C, 12µs propagation delay (10mV overdrive), ±10mV input offset, open-drain output with 11V swing referenced to V−, and compatibility with µMAX-8 package layout constraints.

Technical Context

The MAX971CUA integrates a precision bandgap reference (1.182V ±1%, 0°C to +70°C) and a single comparator with hysteresis control via dedicated HYST pin. Its input common-mode range extends from V− to (V+ − 1.3V), and it uses an N-channel open-drain output stage sinking to GND-not V−-enabling true level-shifting between bipolar and single-ended domains.

Unlike MAX972/MAX974 variants, the MAX971CUA includes both reference and hysteresis circuitry on-die and provides separate GND and V− pins. The HYST pin accepts voltages from (REF − 50mV) to REF, allowing user-programmed hysteresis bands up to 100mV without external feedback resistors or op-amp-based solutions.

Key Specifications

Pinout & Package

Package: 8-pin µMAX (3mm × 3mm, 0.5mm pitch), thermally enhanced exposed pad variant not specified; pin-compatible with SO-8 and PDIP-8 footprints but with reduced board area.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX981CUA, the MAX971CUA offers tighter reference accuracy for precision thresholding; compared with TLV3701IDBVR, it delivers integrated reference, programmable hysteresis, and GND-referenced open-drain output-making it superior for level translation and battery-monitoring applications where component count and layout simplicity matter.

Availability

MAX971CUA is available at Aetrix Electronics and suitable for battery-powered systems, threshold detectors, window comparators, and level translators requiring stable component supply with guaranteed commercial-temperature performance (0°C to +70°C).

Supply support for MAX971CUA 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 communications markets.

The MAX971CUA belongs to the MAX97x/MAX98x micropower comparator family, engineered specifically for ultra-low-power sensing and monitoring in space-constrained, battery-operated equipment.

FAQ

What is the maximum supply voltage for the MAX971CUA?

The MAX971CUA supports a total supply voltage (V+ − V−) up to 11V in single-supply mode or ±5.5V in dual-supply mode. Absolute maximum ratings specify V+ to V− as +12V, but functional operation is guaranteed only up to 11V. Exceeding this may cause permanent damage. The MAX971CUA's output stage can tolerate up to 11V above V− regardless of supply presence-enabling hot-swap and level-shifting use cases where V+ is absent.

Does the MAX971CUA require external hysteresis components?

No-the MAX971CUA includes a dedicated HYST pin that enables programmable hysteresis using just two external resistors between REF, HYST, and V−. This eliminates the need for external positive-feedback networks or op-amp-based hysteresis circuits. When HYST is tied directly to REF, hysteresis is disabled. The MAX971CUA's internal architecture ensures fast, low-current hysteresis action-unlike discrete solutions that increase supply current and propagation delay.

Can the MAX971CUA operate from a 3V supply?

Yes-the MAX971CUA is fully specified for 3V single-supply operation (V+ = 3V, V− = GND). At 3V, typical supply current is 2.4µA–3.0µA, input offset remains ±10mV, and propagation delay increases slightly to ~14µs (10mV overdrive). The internal 1.182V reference remains stable and accurate, supporting reliable threshold detection in 3V microcontroller systems without external regulation.

What is the purpose of the separate GND pin on the MAX971CUA?

The separate GND pin (Pin 1) provides a dedicated ground return path for the open-drain output transistor-distinct from the V− supply rail (Pin 2). This allows the output to sink current to system ground while inputs and reference remain referenced to V−, enabling true level translation between bipolar supplies (e.g., ±5V) and single-ended logic (e.g., 3.3V). Without this separation, the MAX971CUA could not perform bipolar-to-single-ended conversion-a key differentiator versus standard comparators.

Is the internal reference of the MAX971CUA buffered or unbuffered?

The internal 1.182V reference of the MAX971CUA is unbuffered-its output (Pin 6, REF) is directly connected to the bandgap core and must not be bypassed with capacitors. It is rated to source up to 25µA and sink up to 15µA while maintaining ±1% accuracy. Loading beyond these limits will degrade reference voltage accuracy and increase output impedance. For applications requiring higher drive strength or lower noise, an external buffer amplifier must be used-but doing so adds power and complexity the MAX971CUA was designed to avoid.