Analog Devices Inc./Maxim Integrated MAX6429DJUR+T

Overview

MAX6429DJUR+T from Maxim Integrated is a factory-trimmed, single-output, low-power battery monitor IC for Li+ and alkaline/NiMH/NiCd cells, featuring 2.0V low-threshold, 2.7V high-threshold, 140ms LBO timeout, and push-pull active-low LBO output in SOT23-3 package. It asserts LBO when battery voltage falls below 2.0V and deasserts only after rising above 2.7V and holding for ≥140ms - enabling stable low-power mode transitions in portable medical devices and pagers.

For engineers reviewing the MAX6429DJUR+T datasheet, MAX6429DJUR+T pinout, MAX6429DJUR+T application, or MAX6429DJUR+T equivalent, this device delivers verified hysteresis-based battery state detection with guaranteed LBO logic validity down to 1.0V supply, sub-1.5µA quiescent current, and operation across –40°C to +85°C - critical for space-constrained, long-life battery systems.

Technical Context

The MAX6429DJUR+T implements a dual-comparator architecture with internal 615mV reference, fixed hysteresis (ΔV = 0.7V), and integrated timing circuitry to enforce a minimum 140ms LBO deassertion delay. Its BATT-powered operation eliminates need for external VDD regulation.

It uses direct battery-voltage sensing without external resistors, supports push-pull LBO output referenced to BATT, and guarantees valid logic states even at BATT = 1.0V - ensuring reliable wake-up signaling in deeply discharged conditions.

Key Specifications

Pinout & Package

SOT23-3 package (3-pin, 1.4mm × 2.9mm × 1.1mm), lead-free, tape-and-reel. Pin 1 = BATT, Pin 2 = LBO, Pin 3 = GND - no external components required.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6429DJUR+T, MAX6428DJUR+T offers slightly lower thresholds for earlier warning in NiMH systems, while TLV7031DBVR trades integration for flexibility - requiring design effort to replicate hysteresis, timeout, and ultra-low I_Q in a discrete solution.

Availability

MAX6429DJUR+T is available at Aetrix Electronics and suitable for portable medical sensors, pagers, electronic toys, and MP3 players requiring stable component supply with guaranteed long-term manufacturability and RoHS-compliant packaging.

Supply support for MAX6429DJUR+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 management, sensing, and interface applications in industrial, medical, and portable electronics.

The MAX6427–MAX6438 family was engineered specifically for ultra-low-power battery-state monitoring in space-constrained, long-life portable systems - prioritizing sub-2µA quiescent current, factory-trimmed accuracy, and robust noise immunity.

FAQ

What is the exact low-battery threshold voltage for MAX6429DJUR+T?

The MAX6429DJUR+T has a factory-trimmed low-threshold voltage (VLTH) of 2.0V ±2.5%, specified over –40°C to +85°C. This value is fixed and unadjustable - it triggers LBO assertion when battery voltage falls below 2.0V. The corresponding high-threshold (VHTH) is 2.7V ±2.5%, and the device holds LBO asserted until BATT rises above 2.7V and remains there for ≥140ms. These values are confirmed in the MAX6427–MAX6438 datasheet Tables 1 and 2 under DJ code.

Does MAX6429DJUR+T require external resistors or capacitors to operate?

No, MAX6429DJUR+T requires no external components. It is a fully self-contained battery monitor with internal reference, comparators, and timing circuitry. The SOT23-3 footprint connects only BATT, GND, and LBO - eliminating resistor dividers, pull-ups, or debounce capacitors. This is explicitly stated in the datasheet's "No External Components Required" feature and validated in the Typical Operating Circuit (Figure 1).

What output type does MAX6429DJUR+T use, and how is it interfaced?

MAX6429DJUR+T features an active-low push-pull LBO output. It actively drives low (≤0.4V at 3.2mA sink) when asserted and actively drives high (≥0.8×BATT) when deasserted - no external pull-up is needed. This allows direct connection to microcontroller NMI, reset, or enable pins. The output is referenced to BATT, not VDD, enabling operation across the full 1.0V–5.5V supply range.

Can MAX6429DJUR+T operate reliably at 1.0V battery voltage?

Yes, MAX6429DJUR+T guarantees valid LBO logic states down to BATT = 1.0V - a key specification confirmed in the Electrical Characteristics table and Applications section. At 1.0V, the LBO output remains functional: it asserts low when VLTH is crossed and maintains defined VOL/VOH margins. This ensures fail-safe shutdown signaling in deeply discharged alkaline or NiMH cells, unlike many comparators that cease operation below 1.5V.

How does the 140ms timeout function in MAX6429DJUR+T, and is it adjustable?

The 140ms minimum timeout in MAX6429DJUR+T is an internal, non-adjustable timer that enforces delay between BATT crossing VHTH and LBO deassertion. It prevents chattering during battery recovery transients and is temperature-stable (±15% over –40°C to +85°C per Figure toc02). This timing is hard-coded in silicon - no external capacitor or resistor can modify it, ensuring consistent behavior across units and conditions.