Analog Devices Inc./Maxim Integrated MAX971EPA

Overview

The MAX971EPA from Maxim Integrated is a single, ultra-low-power, open-drain comparator with integrated 1.182V ±1% precision voltage 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 supply current over temperature, supports rail-to-rail input range down to V− and within 1.3V of V+, and is used in battery-powered threshold detectors requiring stable low-power operation.

For engineers reviewing the MAX971EPA datasheet, MAX971EPA pinout, MAX971EPA application, or MAX971EPA equivalent, key selection criteria include its guaranteed −40°C to +85°C extended temperature range, separate GND pin for output stage enabling bipolar-to-single-ended level translation, 12µs propagation delay at 10mV overdrive, and compatibility with 8-pin PDIP packaging for through-hole prototyping and industrial control interfaces.

Technical Context

The MAX971EPA integrates a bandgap voltage reference referenced to V− (not GND), delivering 1.182V ±1% accuracy across −40°C to +85°C. Its comparator features an open-drain N-channel MOSFET output sinking to GND - distinct from MAX972/MAX973 variants that sink to V− - enabling direct interfacing with higher-voltage logic domains up to 11V.

Hysteresis is implemented externally using two resistors between REF and HYST pins, allowing user-defined hysteresis bands up to 100mV without feedback loops or layout-sensitive positive feedback networks. Input common-mode range extends from V− to (V+ − 1.3V), supporting operation near supply rails in low-voltage systems such as 3V sensor monitoring and 5V power-good detection.

Key Specifications

Pinout & Package

MAX971EPA is housed in an 8-pin plastic DIP package with through-hole mounting. 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+, and Pin 8 is GND. The GND pin is dedicated to the output transistor's source terminal, decoupling output switching from analog ground paths.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX971CPA, the MAX971EPA delivers identical performance with extended temperature qualification, while TLV3701IP trades integration for lower quiescent current - making MAX971EPA optimal for robust, compact, reference-free threshold detection in harsh environments.

Availability

MAX971EPA is available at Aetrix Electronics and suitable for battery-powered systems, power-good monitoring, level translation, and window comparator applications requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for MAX971EPA 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 MAX971EPA belongs to Maxim's micropower comparator family, engineered specifically for ultra-low-power, self-contained threshold detection in resource-constrained systems where integration of reference and hysteresis reduces design risk and bill-of-materials cost.

FAQ

What is the operating temperature range of the MAX971EPA?

The MAX971EPA is specified for operation from −40°C to +85°C, qualifying it for extended-temperature industrial, automotive, and outdoor applications. This range is confirmed in the Ordering Information table and applies to all electrical characteristics unless otherwise noted. Unlike the MAX971CPA variant, the MAX971EPA maintains its ≤4µA supply current and ±1% reference accuracy across this full span, making it suitable for deployments where ambient conditions exceed commercial limits.

Does the MAX971EPA require an external reference for basic comparator operation?

No, the MAX971EPA includes an internal 1.182V ±1% bandgap voltage reference accessible at the REF pin, eliminating the need for external references in most threshold-detection applications. This reference is referenced to V−, not GND, and can source up to 6µA or sink 4µA over temperature. For applications requiring tighter tolerance or different voltage levels, an external reference may be used, but the internal reference is fully functional and characterized for standalone use in the MAX971EPA.

Can the MAX971EPA operate from a 3V single supply?

Yes, the MAX971EPA operates from a minimum single supply of 2.5V, making 3V fully supported. At 3V, typical supply current is 3.0µA (C temp range) or 3.8µA (E temp range), and propagation delay remains ≤12µs at 10mV overdrive. Input common-mode range extends from V− (GND) to 1.7V, accommodating most 3V sensor outputs. The internal reference remains stable and accurate, enabling reliable low-voltage threshold detection without performance degradation.

How is hysteresis implemented on the MAX971EPA?

Hysteresis on the MAX971EPA is implemented using the HYST pin: connect resistor R1 between REF and HYST, and R2 between HYST and V−. The hysteresis band (VHB) ≈ 2 × (VREF − VHYST), adjustable from 0mV (HYST = REF) to 100mV (HYST = REF − 50mV). This method avoids external feedback loops, reduces layout sensitivity, and consumes negligible current - unlike traditional positive-feedback hysteresis. The MAX971EPA datasheet provides exact equations for R1/R2 selection based on desired VHB and IREF.

What is the purpose of the separate GND pin on the MAX971EPA?

Pin 8 (GND) on the MAX971EPA is the dedicated source terminal for the open-drain output MOSFET, electrically isolated from V− (Pin 2). This allows the output to sink current to a clean logic ground while the comparator core references V−, enabling robust bipolar-to-single-ended level translation (e.g., ±5V input → 3.3V output). It prevents output switching noise from coupling into the analog supply rail, improving noise immunity in mixed-signal systems - a key distinction from variants like MAX972 that sink to V− instead.