Analog Devices Inc./Maxim Integrated MAX971CSA-T

Overview

The MAX971CSA-T 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 quiescent current over temperature, supports rail-to-rail input range (V− to V+ −1.3V), 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 MAX971CSA-T datasheet, MAX971CSA-T pinout, MAX971CSA-T application, or MAX971CSA-T equivalent, this page delivers verified specifications, validated pin functions, confirmed use cases in low-voltage monitoring and level-shifting circuits, and two technically documented alternative comparators with explicit functional and accuracy differences.

Technical Context

The MAX971CSA-T integrates a bandgap voltage reference referenced to V− (not GND), delivering 1.182V ±1% over 0°C to +70°C, with source/sink capability up to 25µA/15µA. Its comparator core uses micropower architecture enabling operation down to 2.5V supply while maintaining guaranteed input common-mode range from V− to V+ −1.3V.

Hysteresis is implemented externally via the HYST pin using two resistors between REF and V−, allowing adjustable hysteresis bands up to 100mV without feedback loops or layout-sensitive positive feedback networks. The open-drain output sinks to GND (not V−), supporting wire-OR configurations and 11V-level translation even with no active V+ supply.

Key Specifications

Pinout & Package

MAX971CSA-T is housed in an 8-pin SO (Small Outline) package with gull-wing leads, JEDEC MS-012AC compliant, 150-mil body width, and standard SOIC footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX971CSA-T, MAX921CSA-T offers push-pull output for direct CMOS driving but forfeits level-shifting capability, while TLV3701IDBVR reduces current draw by 68% yet adds BOM cost and layout complexity due to missing reference.

Availability

MAX971CSA-T is available at Aetrix Electronics and suitable for battery-powered systems, threshold detectors, level translators, and oscillator control circuits requiring stable component supply with guaranteed long-term availability.

Supply support for MAX971CSA-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) is a semiconductor company specializing in high-performance analog and mixed-signal ICs for power, sensing, and interface applications.

The MAX971CSA-T belongs to Maxim's ultra-low-power comparator family designed specifically for energy-constrained applications such as portable medical devices, IoT endpoints, and industrial sensor nodes where micropower operation and integrated precision references are critical.

FAQ

What is the reference voltage tolerance of the MAX971CSA-T over temperature?

The MAX971CSA-T features a 1.182V internal bandgap reference with ±1% accuracy over the commercial temperature range (0°C to +70°C). This specification is guaranteed-not typical-and applies across the full operating supply range (2.5V to 11V). The reference is referenced to V−, not GND, so its absolute output voltage shifts with V− potential; MAX971CSA-T users must account for this in level-sensitive designs.

Can the MAX971CSA-T operate from a 1.8V supply?

No, the MAX971CSA-T is not specified to operate below 2.5V supply. While some comparators in the MAX97x/MAX98x family (e.g., MAX974) may function down to 1V, the MAX971CSA-T's datasheet guarantees performance only from 2.5V to 11V. Operation below 2.5V risks undefined reference behavior, increased propagation delay, and reduced output sink current-making it unsuitable for 1.8V systems without validation.

How is hysteresis configured on the MAX971CSA-T?

Hysteresis on the MAX971CSA-T is configured using the HYST pin: connect R1 between REF and HYST, and R2 between HYST and V−. The hysteresis band (V_HB) equals approximately 2 × (V_REF − V_HYST), with V_HYST adjustable from REF −50mV to REF. For example, setting V_HYST = REF −25mV yields ~50mV hysteresis. MAX971CSA-T's HYST network draws negligible current (<0.02nA), preserving accuracy.

Does the MAX971CSA-T require a bypass capacitor on the REF pin?

No, the MAX971CSA-T datasheet explicitly states "Do not bypass the REF output." Adding capacitance to the REF pin destabilizes the internal reference regulation loop and increases noise susceptibility. Instead, maintain short, low-impedance traces to HYST and minimize coupling from noisy signals (especially OUT) to REF. Power supply bypassing (e.g., 100nF at V+) is recommended only if supply impedance is high.

What is the maximum output sink current of the MAX971CSA-T?

The MAX971CSA-T output can sink up to 50mA continuously (absolute maximum rating), but its practical sink current depends on V+ and load conditions. At V+ = 5V and V_OL = 0.4V, it delivers 1.8mA; at V+ = 3V, sink current drops to 0.8mA. Designers must verify VOL vs. I_OUT curves in the datasheet for their specific V+ and logic-high threshold requirements-MAX971CSA-T's output stage is optimized for low-current, high-impedance pullup interfaces.