Analog Devices Inc./Maxim Integrated MAX981CSA+T

Overview

The MAX981CSA+T from Maxim Integrated is a single, ultra-low-power, open-drain comparator with integrated 1.182V ±2% bandgap 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 MAX981CSA+T datasheet, MAX981CSA+T pinout, MAX981CSA+T application, or MAX981CSA+T equivalent, key selection criteria include its 4µA max supply current at extended temperature, 12µs propagation delay (10mV overdrive), ±2% reference accuracy, open-drain output with 11V output voltage range, and HYST-pin-based hysteresis programming without external feedback.

Technical Context

The MAX981CSA+T integrates a precision 1.182V bandgap reference referenced to V− (not GND), with ±2% tolerance over 0°C to +70°C, capable of sourcing up to 25µA and sinking up to 15µA. Its comparator core features rail-to-rail input operation (V− to V+ − 1.3V), <±10mV input offset voltage, and <±5nA input leakage current.

Hysteresis is implemented via the HYST pin: connecting two external resistors between REF, HYST, and V− sets a hysteresis band up to 100mV (REF − HYST ≤ 50mV). The open-drain output sinks to GND (separate GND pin), enabling wire-OR configurations and level-shifting across domains up to 11V above V−.

Key Specifications

Pinout & Package

MAX981CSA+T is housed in an 8-pin SO (Small Outline) package per JEDEC MS-012, with gull-wing leads, 1.27mm pitch, and standard SOIC footprint compatibility.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX971CSA+, the MAX981CSA+ trades ±1% reference accuracy for lower cost and broader tolerance margin; compared with TLV3701IDBVR, it delivers integrated reference and HYST-pin hysteresis at higher quiescent current-making it optimal for cost-sensitive, self-contained threshold detection where 4µA is acceptable.

Availability

MAX981CSA+T is available at Aetrix Electronics and suitable for battery-powered systems, threshold detectors, level translators, and oscillator circuits requiring stable component supply and long-term manufacturability.

Supply support for MAX981CSA+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 in industrial, medical, and consumer systems.

The MAX981CSA+T belongs to the MAX97x/MAX98x micropower comparator family, engineered specifically for ultra-low-power, self-contained voltage monitoring and level translation in space- and energy-constrained applications.

FAQ

What is the maximum supply voltage for the MAX981CSA+T?

The MAX981CSA+T supports a single-supply voltage range of 2.5V to 11V, or dual supplies from ±1.25V to ±5.5V. Absolute maximum ratings specify V+ to V− up to 12V, but functional operation is guaranteed only up to 11V. Exceeding 11V may cause permanent damage. The MAX981CSA+T's output stage can tolerate up to 11V above V− even when V+ is unpowered-enabling robust level-shifting functionality.

Does the MAX981CSA+T require an external reference?

No, the MAX981CSA+T includes an internal 1.182V ±2% bandgap voltage reference accessible at the REF pin. This reference is referenced to V−, not GND, and is designed to drive the HYST pin and serve as a stable threshold source for both comparator inputs. Bypassing the REF pin is explicitly discouraged per the datasheet, and no external reference is needed for standard operation of the MAX981CSA+T.

How is hysteresis configured on the MAX981CSA+T?

Hysteresis on the MAX981CSA+T is configured using the HYST pin: connect resistor R1 between REF and HYST, and resistor R2 between HYST and V−. The hysteresis band (VHB) ≈ 2 × (VREF − VHYST), with VHYST adjustable from VREF down to VREF − 50mV-yielding up to 100mV total hysteresis. For example, setting VHYST = VREF − 25mV gives ~50mV hysteresis. This method replaces external positive-feedback networks and is intrinsic to the MAX981CSA+T's architecture.

What is the purpose of the separate GND pin on the MAX981CSA+T?

Pin 8 (GND) on the MAX981CSA+T is the dedicated ground connection for the output-stage N-channel MOSFET. It is electrically isolated from the signal ground (V−) and enables the output to sink current to a different ground domain-allowing level translation between isolated voltage domains (e.g., converting ±5V signals to 3.3V logic). This architecture makes the MAX981CSA+T ideal for bipolar-to-single-ended conversion, unlike comparators with output tied to V−.

Can the MAX981CSA+T operate from a 3V supply?

Yes, the MAX981CSA+T is fully specified and functional at 3V single supply (V+ = 3V, V− = GND). Electrical characteristics-including 4µA max supply current, 12µs propagation delay, and ±2% reference accuracy-are guaranteed across 2.5V to 11V. At 3V, input common-mode range extends from 0V to 1.7V, and output low voltage remains ≤0.4V at 1.8mA sink current-making it well-suited for modern low-voltage portable systems using the MAX981CSA+T.