Analog Devices Inc./Maxim Integrated MAX6429EHUR-T

Overview

MAX6429EHUR-T from Maxim Integrated is a factory-trimmed, single-output, low-power battery monitor IC for Li+ and multi-cell alkaline/NiMH/NiCd systems. It features a fixed low-threshold of 2.9V (±2.5%), high-threshold of 3.1V (±2.5%), 140ms minimum LBO timeout, 1µA typical supply current, and operates from 1.0V to 5.5V. It delivers active-low push-pull LBO output for direct microprocessor NMI or system shutdown control in portable medical devices.

For engineers reviewing the MAX6429EHUR-T datasheet, MAX6429EHUR-T pinout, MAX6429EHUR-T application, or MAX6429EHUR-T equivalent, this device serves as a precision, ultra-low-quiescent battery health indicator with guaranteed valid logic down to BATT = 1.0V, immunity to short voltage transients, and no external components required.

Technical Context

The MAX6429EHUR-T implements a dual-comparator architecture with internal 615mV reference and hysteresis timing logic to detect battery voltage crossing of factory-set thresholds. Its LBO output asserts when BATT falls below VLTH (2.9V) and deasserts only after BATT rises above VHTH (3.1V) and remains stable for ≥140ms - preventing false triggers during battery recovery.

This device uses BiCMOS process technology (905 transistors), supports operation from -40°C to +85°C, and draws just 1µA typical supply current at 3.7V. It interfaces directly to microprocessor NMI inputs or power-enable circuitry without level-shifting or external pull-ups.

Key Specifications

Pinout & Package

MAX6429EHUR-T is housed in a 3-pin SOT23-3 package (JEDEC MO-178AA), with 1.3mm × 2.9mm footprint and 1.45mm max height. Pin 1 = BATT, Pin 2 = LBO, Pin 3 = GND.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6428EHUR-T and TLV7031DBVR, the MAX6429EHUR-T provides optimal balance of precision (2.9V/3.1V), zero-component simplicity, and guaranteed 1.0V operation - making it ideal for volume portable devices where calibration overhead and bill-of-materials cost must be minimized.

Availability

MAX6429EHUR-T is available at Aetrix Electronics and suitable for portable medical devices, cordless phones, pagers, and electronic toys requiring stable component supply and long-term lifecycle support.

Supply support for MAX6429EHUR-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 analog, mixed-signal, and power management ICs for industrial, communications, and consumer applications.

The MAX6427–MAX6438 family was designed specifically for ultra-low-power battery health monitoring in space-constrained portable electronics, emphasizing factory-trimmed accuracy, sub-µA operation, and robust transient immunity.

FAQ

What is the exact low-battery threshold voltage of the MAX6429EHUR-T?

The MAX6429EHUR-T has a factory-trimmed low-threshold voltage (VLTH) of 2.9V with ±2.5% tolerance over temperature. This value is laser-trimmed during production and does not require external calibration. The MAX6429EHUR-T uses this threshold to assert its active-low push-pull LBO output when battery voltage falls below 2.9V.

Does the MAX6429EHUR-T require external resistors or capacitors to operate?

No, the MAX6429EHUR-T requires no external components. Its thresholds are factory-trimmed, its 615mV internal reference is integrated, and its 140ms timeout is implemented on-die. Only three connections are needed: BATT, GND, and LBO - enabling minimal footprint and zero calibration overhead in production.

Can the MAX6429EHUR-T operate reliably at battery voltages below 1.6V?

Yes, the MAX6429EHUR-T guarantees valid LBO logic state down to BATT = 1.0V, per the Absolute Maximum Ratings and Electrical Characteristics tables. This allows full end-of-discharge monitoring for alkaline/NiMH cells and supports safe shutdown before irreversible battery damage occurs.

What is the function of the 140ms timeout period in the MAX6429EHUR-T?

The 140ms minimum timeout ensures the LBO output remains asserted for at least that duration after BATT rises above the high threshold (3.1V). This prevents premature re-enabling of system power or processor activity during battery recovery transients. The MAX6429EHUR-T enforces this delay internally - no external timing components are needed.

Is the MAX6429EHUR-T pin-compatible with other devices in the MAX6427–MAX6438 family?

The MAX6429EHUR-T shares the same 3-pin SOT23-3 package and pinout (BATT–LBO–GND) with MAX6427xxUR-T and MAX6428xxUR-T variants. However, it is not pin-compatible with 4-pin (SOT143), 5-pin (SOT23-5), or 6-pin (SOT23-6) members of the family, which provide dual outputs or user-adjustable thresholds and different pin assignments.