Analog Devices Inc./Maxim Integrated MAX6440UTEHRD3

Overview

MAX6440UTEHRD3 from Maxim Integrated is a single-output, ultra-low-power battery monitor with integrated microprocessor supervisor. It features factory-trimmed 3.00V/3.15V hysteresis thresholds for Li+ or alkaline/NiMH batteries, 2.5µA typical supply current at 3.6V, push-pull active-low RESET output, and 150ms minimum reset timeout - used in portable medical devices to enable graceful low-power state transitions before shutdown.

For engineers reviewing the MAX6440UTEHRD3 datasheet, MAX6440UTEHRD3 pinout, MAX6440UTEHRD3 application, or MAX6440UTEHRD3 equivalent, key selection criteria include its fixed VCC reset threshold (3.00V min), dual-voltage monitoring capability (VBATT + VCC), manual reset debounce timing (150ms), and SOT23-6 package compatibility with space-constrained handheld designs.

Technical Context

The MAX6440UTEHRD3 integrates a precision 1.23V reference, dual comparators, and timing logic to independently monitor VBATT (1.2V–5.5V) and VCC (1.2V–5.5V). Its LBO output asserts when VBATT falls below 2.925V (LTH) and deasserts only after rising above 3.075V (HTH) for ≥150ms, providing noise-immune hysteresis.

The device delivers an active-low push-pull RESET output triggered by VCC falling below 3.000V (VTH), with guaranteed assertion for ≥150ms after VCC recovers. MR input includes internal 1.5kΩ pullup and 150ms rising-edge debounce to suppress switch bounce during manual reset.

Key Specifications

Pinout & Package

SOT23-6 package with 1.95mm body width, 0.95mm height, and 0.95mm lead pitch; JEDEC MO-178 compliant; lead-free (RoHS) option available.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6439UTEHRD3, the MAX6440UTEHRD3's push-pull RESET reduces external component count and improves noise immunity; versus TPS3808G30DBVR, it adds essential dual-supply monitoring but consumes slightly higher current - making it optimal for battery-critical portable systems needing both functions in one die.

Availability

MAX6440UTEHRD3 is available at Aetrix Electronics and suitable for portable medical devices, industrial sensor nodes, Li+ battery-powered handhelds, and educational electronics requiring stable component supply across extended production lifecycles.

Supply support for MAX6440UTEHRD3 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, sensing, and interface applications in demanding industrial, medical, and communications systems.

The MAX6439–MAX6442 family was engineered specifically for ultra-low-power battery-operated systems requiring simultaneous VCC supervision and accurate, hysteresis-equipped battery voltage monitoring in minimal footprint.

FAQ

What is the exact factory-trimmed VBATT threshold pair for MAX6440UTEHRD3?

The MAX6440UTEHRD3 has a factory-trimmed lower threshold (LTH) of 2.925V and upper threshold (HTH) of 3.075V, corresponding to the "E" suffix in the part number per Table 1 of the datasheet. This 150mV hysteresis ensures stable LBO assertion/deassertion during battery voltage fluctuations in single-cell Li+ applications.

Does MAX6440UTEHRD3 support both VBATT and VCC as power sources?

Yes, MAX6440UTEHRD3 automatically selects the higher of VBATT or VCC as its internal power source. When VBATT > VCC, the device draws current from the battery; when VCC > VBATT, it operates from the system rail - enabling seamless operation during battery charging or AC adapter use without external power-path control.

What is the function of the MR pin on MAX6440UTEHRD3 and how is it debounced?

The MR pin on MAX6440UTEHRD3 is an active-low manual reset input with internal 1.5kΩ pullup to VCC. It triggers a one-shot RESET pulse for the MR timeout period (150ms min). The MR input is hardware-debounced for rising edges only, ignoring pulses within 150ms of a valid assertion to prevent false resets from mechanical switch bounce.

Can MAX6440UTEHRD3 be used with a 1.8V microcontroller reset input?

Yes, MAX6440UTEHRD3's push-pull RESET output guarantees VOH ≥ 0.8 × VCC when VCC ≥ 2.55V and ISOURCE = 500µA, and VOL ≤ 0.3V when asserted. With VCC = 3.3V, RESET swings rail-to-rail and is fully compatible with 1.8V µP reset inputs via appropriate level translation or direct interface if the µP accepts 3.3V-tolerant reset signals.

What package type and dimensions does MAX6440UTEHRD3 use?

MAX6440UTEHRD3 uses the SOT23-6 package: 2.8mm × 2.9mm body size, 0.95mm maximum height, 0.95mm lead pitch, and JEDEC MO-178 compliant outline. Pin 1 is marked with a dot; the package supports reflow soldering and is available in both leaded and RoHS-compliant lead-free versions.