Analog Devices Inc./Maxim Integrated MAX921ESA-T

Overview

The MAX921ESA-T from Maxim Integrated is a single, ultra-low-power, rail-to-rail input comparator with integrated 1.182V ±1% bandgap reference, programmable hysteresis via HYST pin, and TTL/CMOS-compatible output capable of sourcing up to 40mA. It operates from +2.5V to +11V single supply (or ±1.25V to ±5.5V dual supply), features 4μA max quiescent current over –40°C to +85°C, and supports threshold detection in battery-powered instrumentation.

For engineers reviewing the MAX921ESA-T datasheet, MAX921ESA-T pinout, MAX921ESA-T application, or MAX921ESA-T equivalent, key selection criteria include guaranteed hysteresis implementation without external feedback, internal reference accuracy over temperature, output drive capability into capacitive loads, and compatibility with 3V/5V systems requiring minimal supply current.

Technical Context

The MAX921ESA-T integrates a micropower comparator core with a precision bandgap reference referenced to V–, not GND. Its unique output stage eliminates crowbar current during transitions, reducing supply-line parasitic feedback and enabling stable operation without tight layout constraints.

Input common-mode range extends from V– to (V+ – 1.3V); hysteresis is implemented by biasing the HYST pin between REF and (REF – 50mV), yielding up to 100mV hysteresis band. Propagation delay is 12μs typical at 10mV overdrive with 100pF load.

Key Specifications

Pinout & Package

MAX921ESA-T is housed in an 8-pin SO (Small Outline) package, RoHS-compliant, with standard 1.27mm pitch and JEDEC MS-012AC outline.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TLV3701IDBVR and LMV7235M5X, the MAX921ESA-T uniquely combines internal 1.182V reference, HYST pin for hysteresis programming, and 40mA output drive in a single 8-pin SO package-making it optimal for space-constrained, self-contained threshold detection where supply current, accuracy, and drive strength must coexist.

Availability

MAX921ESA-T is available at Aetrix Electronics and suitable for battery-powered instrumentation, industrial sensor interfaces, and power sequencing circuits requiring stable component supply, long-term lifecycle support, and guaranteed extended-temperature performance.

Supply support for MAX921ESA-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, interface, and timing applications in industrial, automotive, and communications markets.

The MAX921ESA-T belongs to the MAX921–MAX924 micropower comparator family, engineered specifically for ultra-low-quiescent-current threshold detection in resource-constrained, battery-operated systems where internal reference and hysteresis simplification reduce design complexity.

FAQ

What is the maximum supply voltage for MAX921ESA-T in single-supply operation?

The MAX921ESA-T supports a single-supply voltage range of +2.5V to +11V. At +11V, it remains within absolute maximum ratings and maintains specified performance across its –40°C to +85°C operating temperature range. Exceeding +11V risks permanent damage per Absolute Maximum Ratings.

Does MAX921ESA-T require external bypass capacitors on V+ and REF pins?

No-bypass capacitors are not required on V+ if supply impedance is low, and REF must never be bypassed. The MAX921ESA-T's crowbar-free output architecture minimizes supply transients, and the internal reference is optimized for direct connection to HYST or external dividers without decoupling.

Can MAX921ESA-T operate from a dual ±5V supply?

Yes-the MAX921ESA-T supports dual supplies from ±1.25V to ±5.5V. When operated at ±5V, its output swings from V+ (+5V) to GND, maintaining TTL compatibility, while inputs accept signals from V– (–5V) to (V+ – 1.3V = +3.7V), enabling bipolar signal monitoring.

How is hysteresis programmed on MAX921ESA-T without external feedback?

Hysteresis is programmed by connecting two resistors between REF, HYST, and V–. The voltage at HYST sets the hysteresis band (up to 100mV). This method avoids positive feedback loops, eliminates stability concerns, and requires no iterative calculations-only basic resistor selection based on desired VHB.

What is the guaranteed output source current for MAX921ESA-T at 25°C?

The MAX921ESA-T guarantees ≥40mA continuous output source current at TA = +25°C, V+ = 5V, and V– = GND. This is confirmed in Typical Operating Characteristics (Figure MAX921/924-TOC17) and enables direct driving of LEDs, small solenoids, or logic inputs without external buffers.