Analog Devices Inc./Maxim Integrated MAX971ESA-T

Overview

The MAX971ESA-T 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 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 MAX971ESA-T datasheet, MAX971ESA-T pinout, MAX971ESA-T application, or MAX971ESA-T equivalent, key selection criteria include its guaranteed ±1% reference accuracy over 0°C to +70°C, 12µs propagation delay at 10mV overdrive, open-drain output capable of 11V swing referenced to V−, and HYST-pin hysteresis programming without external feedback networks.

Technical Context

The MAX971ESA-T integrates a precision bandgap reference (1.182V ±1%) referenced to V−, not GND, and a single comparator with input common-mode range from V− to (V+ − 1.3V). Its HYST pin accepts voltages from (REF − 50mV) to REF, enabling user-defined hysteresis bands up to 100mV via two external resistors.

Output stage uses an N-channel MOSFET sinking to dedicated GND pin (Pin 1), decoupling output logic ground from analog supply rails-critical for level-shifting between ±5V and 3.3V domains. Propagation delay is specified at 12µs (high-to-low) under 10mV overdrive with 100pF load and 1MΩ pullup to V+.

Key Specifications

Pinout & Package

MAX971ESA-T is housed in an 8-pin SO (Small Outline) package with gull-wing leads, compliant with JEDEC MS-012, 150-mil body width.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX921ESA-T and TLV3701IDBVR, the MAX971ESA-T uniquely combines integrated ±1% reference, HYST-pin programmability, open-drain output with separate GND, and single/dual-supply flexibility-making it optimal for space-constrained, battery-powered voltage monitoring where reference accuracy and noise immunity are critical.

Availability

MAX971ESA-T is available at Aetrix Electronics and suitable for battery-powered systems, threshold detectors, level translators, and oscillator circuits requiring stable component supply across industrial temperature ranges.

Supply support for MAX971ESA-T 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.

The MAX97x/MAX98x comparator family targets ultra-low-power, high-accuracy voltage monitoring in portable and energy-harvesting systems-emphasizing micropower operation, integrated references, and flexible supply configurations.

FAQ

What is the reference voltage tolerance of the MAX971ESA-T over temperature?

The MAX971ESA-T features a 1.182V internal bandgap reference with ±1% accuracy over the commercial temperature range (0°C to +70°C). At extended temperature (−40°C to +85°C), the reference remains functional but specification degrades to ±2%; this is confirmed in the MAX971EPA/MAX971ESA ordering variants' electrical characteristics tables. The MAX971ESA-T's reference is referenced to V−, not GND, so proper grounding of V− is essential for accuracy.

Can the MAX971ESA-T operate from a 2.0V single supply?

No-the MAX971ESA-T is not guaranteed to operate below 2.5V single supply (or ±1.25V dual supply). While the comparator core may function down to ~1V in some conditions, the internal 1.182V reference ceases regulation below ~2.2V, and key parameters-including supply current, propagation delay, and reference accuracy-are not characterized or guaranteed. For sub-2.5V operation, consider the MAX974 or MAX984 variants, which are explicitly rated for low-voltage use per the datasheet's "Low-Voltage Operation" section.

How is hysteresis programmed on the MAX971ESA-T?

Hysteresis on the MAX971ESA-T is programmed using the HYST pin (Pin 5): connect R1 between REF (Pin 6) and HYST, and R2 between HYST and V− (Pin 2). The hysteresis band (VHB) ≈ 2 × (VREF − VHYST), with VHYST adjustable from (VREF − 50mV) to VREF. For example, setting VHYST = VREF − 25mV yields ~50mV hysteresis. This method avoids external feedback and consumes negligible current-unlike traditional positive-feedback hysteresis circuits.

What is the purpose of the separate GND pin (Pin 1) on the MAX971ESA-T?

The separate GND pin (Pin 1) on the MAX971ESA-T serves exclusively as the return path for the open-drain output transistor-decoupling digital output logic ground from the analog supply rails (V+ and V−). This enables level translation: for example, inputs referenced to ±5V (V+ = +5V, V− = −5V) can produce a 0–3.3V output swing by pulling OUT to a 3.3V rail via external resistor while tying Pin 1 to system GND. Without this pin, output sinking would be referenced to V−, limiting interface flexibility.

Does the MAX971ESA-T require input or reference bypass capacitors?

No bypass capacitor is required on the REF pin-doing so degrades reference stability and increases noise, as explicitly warned in the datasheet. Power-supply bypassing is optional: a 100nF ceramic capacitor is recommended only if supply impedance is high or PCB traces are long; low-impedance lab supplies typically need no bypassing. Input pins (IN+, IN−, HYST) require no bypassing, but layout best practices-short traces, guard rings, and separation from noisy outputs-must be followed to maintain the device's 300µV effective input noise floor.