Analog Devices Inc./Maxim Integrated MAX6431EIUS+T

Overview

The MAX6431EIUS+T from Maxim Integrated is a dual-level, factory-trimmed battery monitor IC with two active-low open-drain low-battery outputs (LBOH and LBOL), 140ms minimum timeout, ±2.5% threshold accuracy over –40°C to +85°C, and 1µA typical supply current. It monitors single Li+ or multi-cell alkaline/NiMH/NiCd batteries to enable system-level power-state transitions - e.g., entering low-power mode on LBOH assertion and full shutdown on LBOL assertion.

For engineers reviewing the MAX6431EIUS+T datasheet, MAX6431EIUS+T pinout, MAX6431EIUS+T application, or MAX6431EIUS+T equivalent, this device supports precise battery-state discrimination in space-constrained portable electronics where ultra-low quiescent current, hysteresis-stabilized thresholds, and dual-output sequencing are critical for reliable power management.

Technical Context

The MAX6431EIUS+T implements two independent comparators with internal hysteresis and fixed factory-trimmed thresholds: VHTH− (upper low-battery trip) and VLTH− (lower low-battery trip), with corresponding deassertion points VHTH+ = 1.05×VHTH− and VLTH+ = 1.05×VLTH−. Its logic ensures LBOH remains asserted ≥140ms after BATT rises above VHTH+, and LBOL remains asserted ≥140ms after BATT rises above VLTH+.

It operates from 1.6V to 5.5V supply (BATT), guarantees valid output logic down to BATT = 1.0V, and features immunity to short voltage transients. The SOT143-4 package integrates all functionality without external components, targeting direct battery monitoring in systems requiring deterministic, noise-immune battery-state signaling.

Key Specifications

Pinout & Package

MAX6431EIUS+T is housed in a lead-free, RoHS-compliant 4-pin SOT143-4 package (1.3mm × 2.1mm body, 0.95mm height), optimized for high-density portable designs. Pin 1 is marked with a dot; pin numbering follows standard SOT143 convention.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar dual-output battery monitor applications.

Compared with MAX6430EIUS+T and TLV809E33DBZR, the MAX6431EIUS+T uniquely delivers dual open-drain outputs with factory-set hysteresis and guaranteed 140ms timeout - enabling robust, hardware-based battery-state sequencing without firmware intervention or external timing components.

Availability

MAX6431EIUS+T is available at Aetrix Electronics and suitable for portable medical devices, electronic toys, MP3 players, and PDAs requiring stable component supply, long-term lifecycle support, and lead-free compliance.

Supply support for MAX6431EIUS+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 precision analog, mixed-signal, and power-management ICs for industrial, medical, and portable applications.

The MAX6427–MAX6438 family was designed specifically for ultra-low-power, dual-threshold battery monitoring in space-constrained, battery-operated systems - eliminating external components while ensuring deterministic, temperature-stable battery-state signaling.

FAQ

What is the exact factory-trimmed threshold voltage pair for MAX6431EIUS+T?

The MAX6431EIUS+T is configured with VHTH− = 3.4V and VLTH− = 2.7V (per Table 1, "EI" suffix). Its corresponding deassertion thresholds are VHTH+ = 3.57V (1.05×3.4V) and VLTH+ = 2.835V (1.05×2.7V). These values are laser-trimmed at wafer test and guaranteed over –40°C to +85°C with ±2.5% tolerance. The MAX6431EIUS+T uses these fixed thresholds without external resistors.

Does MAX6431EIUS+T require external components to operate?

No, the MAX6431EIUS+T requires no external components. As a factory-trimmed dual-output monitor in the MAX6430–MAX6432 series, it integrates precision references, comparators, hysteresis logic, and 140ms timeout circuitry internally. Only bypass capacitor (0.1µF) on BATT is recommended for noise suppression - no resistors, capacitors, or trimming networks are needed for basic operation.

Can MAX6431EIUS+T monitor a single NiMH cell (1.2V nominal)?

Yes, the MAX6431EIUS+T can monitor a single NiMH cell, but only within its valid operating range: BATT must remain ≥1.6V for functional operation (per Electrical Characteristics table). Since a discharged NiMH cell drops to ~1.0V, the device will maintain valid LBOH/LBOL states down to BATT = 1.0V (guaranteed), allowing reliable detection of end-of-discharge at ~1.1V–1.2V depending on load profile.

How does the 140ms timeout in MAX6431EIUS+T improve system reliability?

The 140ms minimum timeout in MAX6431EIUS+T prevents false deassertion of LBOH/LBOL during transient voltage recovery - for example, when a load is removed and battery voltage rebounds briefly. This ensures microcontrollers or DC-DC converters do not re-enable prematurely, avoiding unstable brown-out conditions, data corruption, or erratic peripheral behavior in battery-powered systems.

Is MAX6431EIUS+T pin-compatible with other devices in the MAX6430–MAX6432 family?

Yes, all MAX6430–MAX6432 variants share identical SOT143-4 pinout (BATT, LBOH, GND, LBOL), making them drop-in replacements for threshold changes. However, output logic type differs: MAX6430 uses push-pull LBOH, MAX6431 uses open-drain LBOH/LBOL, and MAX6432 uses open-drain LBOL with active-high LBOH. Always verify output configuration before substitution.