Analog Devices Inc./Maxim Integrated MAX921CUA-T

Overview

The MAX921CUA-T from Maxim Integrated is a single-channel, ultra-low-power voltage 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 0°C to +70°C, and supports threshold detection in battery-powered sensor nodes.

For engineers reviewing the MAX921CUA-T datasheet, MAX921CUA-T pinout, MAX921CUA-T application, or MAX921CUA-T equivalent, this page delivers verified electrical specs, μMAX-8 package layout, hysteresis implementation guidance, and direct alternatives for low-power analog monitoring designs.

Technical Context

The MAX921CUA-T integrates a precision 1.182V reference referenced to V− (not GND), enabling rail-to-rail input common-mode range from V− to (V+ − 1.3V). Its unique output stage eliminates crowbar current during transitions, minimizing supply-line parasitic feedback without requiring external bypassing.

It supports adjustable hysteresis using two external resistors between REF and HYST pins-no feedback loop needed-and delivers 12μs propagation delay at 10mV overdrive with full output swing from V+ to GND under single-supply operation.

Key Specifications

Pinout & Package

Package: 8-pin μMAX (3mm × 3mm, 0.5mm pitch), thermally enhanced, lead-free, RoHS-compliant surface-mount package optimized for space-constrained portable electronics.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LMV331M5X/NOPB and TLV3691IDCKR, the MAX921CUA-T uniquely combines ultra-low IQ, integrated ±1% reference, HYST-pin hysteresis, and 40mA sourcing in a single μMAX-8 package-enabling simpler, more robust low-power threshold detection without external components.

Availability

MAX921CUA-T is available at Aetrix Electronics and suitable for battery-powered systems, threshold detectors, window comparators, and oscillator circuits requiring stable component supply across industrial and consumer production volumes.

Supply support for MAX921CUA-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, mixed-signal, and power management ICs for demanding industrial, medical, and communications applications.

The MAX921CUA-T belongs to the MAX921–MAX924 micropower comparator family, engineered specifically for ultra-low-power sensing and threshold detection in space- and energy-constrained systems.

FAQ

What is the maximum supply voltage for the MAX921CUA-T?

The MAX921CUA-T supports a single-supply voltage range of +2.5V to +11V. When operated from dual supplies, it accepts ±1.25V to ±5.5V. Absolute maximum rating is +12V between V+ and V−, but continuous operation above +11V is not guaranteed per datasheet specifications. The MAX921CUA-T must never be subjected to reverse polarity or voltage exceeding these limits to avoid permanent damage.

Does the MAX921CUA-T require external hysteresis components?

The MAX921CUA-T does not require external hysteresis components for basic operation, but it provides the HYST pin to enable user-adjustable hysteresis using just two resistors. If hysteresis is not needed, connect HYST directly to REF. This architecture avoids feedback loops and complex calculations-unlike conventional comparators-making the MAX921CUA-T especially suited for noise-prone environments where stable switching is critical.

Can the MAX921CUA-T drive an LED directly?

Yes, the MAX921CUA-T can drive an LED directly: its output sources up to 40mA continuously and swings fully from V+ to GND. With V+ = 5V and typical red LED V_F ≈ 1.8V, a 100Ω series resistor limits current to ~32mA-well within safe operating limits. No external transistor or driver is required, simplifying designs like bar-graph indicators or status lights in portable equipment.

Is the internal reference of the MAX921CUA-T referenced to GND or V−?

The internal 1.182V reference of the MAX921CUA-T is referenced to V−, not GND. This means REF = V− + 1.182V. In single-supply operation where V− = GND, REF equals 1.182V relative to GND. However, in dual-supply configurations (e.g., V+ = +5V, V− = −5V), REF = −5V + 1.182V = −3.818V. Designers must account for this when interfacing REF with other circuitry to avoid level-shifting errors.

What is the input common-mode voltage range of the MAX921CUA-T?

The input common-mode voltage range of the MAX921CUA-T is specified from V− to (V+ − 1.3V). For example, with V+ = 5V and V− = 0V (GND), inputs may swing from 0V to 3.7V. This rail-to-rail−1.3V range allows reliable sensing of signals near ground or mid-supply without attenuation or level shifting-critical for accurate battery monitoring and sensor interface applications using the MAX921CUA-T.