Analog Devices Inc./Maxim Integrated MAX931CUA+

Overview

The MAX931CUA+ from Maxim Integrated is a single micropower voltage comparator with integrated 1.182V ±2% bandgap reference, programmable hysteresis via HYST pin, TTL/CMOS-compatible output capable of sourcing up to 40mA, and ultra-low 4µA max supply current over 0°C to +70°C. It operates from +2.5V to +11V single supply (or ±1.25V to ±5.5V dual supply), with input common-mode range extending from V− to V+ − 1.3V - ideal for battery-powered threshold detection in portable instrumentation.

For engineers reviewing the MAX931CUA+ datasheet, MAX931CUA+ pinout, MAX931CUA+ application, or MAX931CUA+ equivalent, key selection considerations include its rail-to-rail input capability, internal reference accuracy and temperature drift, hysteresis programming method using two external resistors, and output drive strength without crowbar current - all critical for low-power analog monitoring circuits requiring stable trip points.

Technical Context

The MAX931CUA+ integrates a precision 1.182V ±2% reference referenced to V− (not GND), enabling self-contained threshold generation without external components. Its comparator features an input stage that accepts signals from V− up to V+ − 1.3V and delivers rail-swinging TTL/CMOS outputs (V+ to GND) with continuous 40mA source/sink capability and no switching crowbar current.

Hysteresis is implemented via the HYST pin, accepting voltages from REF − 50mV to REF; connecting R₁ between REF and HYST and R₂ between HYST and V− sets a symmetric hysteresis band (V_HB ≈ 2 × (REF − V_HYST)), with maximum 100mV achievable. Propagation delay is 12µs typical at 10mV overdrive (5V supply).

Key Specifications

Pinout & Package

MAX931CUA+ is housed in an 8-pin SO (Small Outline) package, 0°C to +70°C operating temperature range, JEDEC MS-012AC compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX921CSA+, MAX931CUA+ trades 1% reference accuracy for lower cost and proven hysteresis simplicity; versus TLV3011IDBVR, it delivers higher output drive and integrated hysteresis control at the expense of slightly higher quiescent current - making it preferable for robust, component-count-sensitive designs.

Availability

MAX931CUA+ is available at Aetrix Electronics and suitable for battery-powered systems, threshold detectors, oscillator circuits, and alarm circuits requiring stable component supply with guaranteed commercial-temperature performance and long-term traceability.

Supply support for MAX931CUA+ 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, mixed-signal, and power-management ICs for industrial, communications, and consumer applications.

The MAX931CUA+ belongs to the MAX93x micropower comparator family, designed specifically for ultra-low-power sensing and monitoring in portable, battery-operated, and energy-harvesting systems where supply current, reference stability, and ease of hysteresis implementation are critical.

FAQ

What is the reference voltage accuracy and temperature drift of the MAX931CUA+?

The MAX931CUA+ features an internal 1.182V bandgap reference with ±2% initial accuracy over the 0°C to +70°C commercial temperature range. The reference is referenced to V−, not GND, and exhibits typical drift of ±100ppm/°C. At +25°C, the reference voltage is specified as 1.158V to 1.206V; full-range min/max values are 1.147V to 1.217V per the datasheet's C-temp specifications.

Can the MAX931CUA+ operate from a 3V single supply?

Yes, the MAX931CUA+ is fully specified for 3V single-supply operation (V+ = 3V, V− = GND). Electrical characteristics including supply current (≤6.2µA typ), input offset voltage (±10mV), and propagation delay (14µs typ at 10mV overdrive) are guaranteed across the 3V condition. Input common-mode range extends from GND to 1.7V, supporting most 3V sensor interfaces.

How is hysteresis programmed on the MAX931CUA+?

Hysteresis on the MAX931CUA+ is programmed using the HYST pin: connect resistor R₁ between REF and HYST, and R₂ between HYST and V− (GND in single-supply mode). The hysteresis band V_HB ≈ 2 × (REF − V_HYST) is adjustable up to 100mV. For example, setting V_HYST = REF − 25mV yields ~50mV hysteresis. No external feedback around the comparator is required.

Does the MAX931CUA+ support dual-supply operation?

Yes, the MAX931CUA+ supports dual-supply operation from ±1.25V to ±5.5V. In this configuration, V+ connects to the positive rail, V− to the negative rail, and GND is left unconnected. The reference (REF) remains referenced to V−, and the output swings from V+ to GND - meaning GND must be at a defined potential (e.g., midpoint) for proper operation. Input common-mode range is V− to V+ − 1.3V.

What is the maximum continuous output source current of the MAX931CUA+?

The MAX931CUA+ delivers ≥40mA continuous output source current into a load tied between OUT and GND, with V+ = 5V and ambient temperature ≤+70°C. This is verified under steady-state conditions with adequate PCB copper pour for thermal dissipation. Short pulses up to 100mA are possible if average power stays within the 471mW SO-package derated limit (TA = +70°C).