Analog Devices Inc./Maxim Integrated MAX6865UK40D5L+T

Overview

The MAX6865UK40D5L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, factory-trimmed 4.000V reset threshold (±2.5%), 450ms minimum reset timeout period, and integrated watchdog timer with 209s typical timeout. It monitors VCC, responds to manual reset (MR) assertion, and triggers reset on watchdog timeout - designed for battery-critical applications like glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK40D5L+T datasheet, MAX6865UK40D5L+T pinout, MAX6865UK40D5L+T application, or MAX6865UK40D5L+T equivalent, this page delivers verified technical context, exact pin functions, real-world timing behavior, and validated alternative options for low-power µP supervision in space- and energy-constrained systems.

Technical Context

The MAX6865UK40D5L+T implements a dual-trigger reset architecture: it asserts reset when VCC falls below 4.000V, when MR is pulled low, or when the watchdog input (WDI) remains static beyond 209s (typ). Its internal watchdog timer clears on any WDI edge, MR assertion, or active reset - ensuring robust detection of firmware hangs without requiring precise pulse timing.

Reset output is active-high push-pull, guaranteed valid down to VCC = 1.1V, with VOH ≥ 0.8×VCC at ISOURCE = 500µA and VOL ≤ 0.3V at ISINK = 1.2mA. The device requires no external components, features 200ns MR glitch rejection, and maintains immunity to VCC transients ≤40µs at 100mV overdrive.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, -40°C to +85°C operating range.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar microprocessor supervisory applications.

Compared with MAX6865UK40D5L+T, TPS3837K33DBVR offers lower cost but sacrifices watchdog safety and nanopower efficiency, while MAX6361KA29D3+T matches footprint but lacks both the 4.000V precision threshold and 209s watchdog - making MAX6865UK40D5L+T uniquely suited for certified medical and long-life battery applications requiring dual-fault supervision.

Availability

MAX6865UK40D5L+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign monitors, industrial handheld scanners, and low-power wireless sensors requiring stable component supply across extended production lifecycles.

Supply support for MAX6865UK40D5L+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 demanding applications in industrial, medical, and communications markets.

The MAX68xx family delivers nanopower supervisory solutions optimized for battery-powered medical devices and portable electronics where ultra-low ICC, guaranteed reset validity at low VCC, and integrated watchdog safety are mandatory.

FAQ

What is the exact reset threshold voltage of the MAX6865UK40D5L+T?

The MAX6865UK40D5L+T has a factory-trimmed reset threshold of 4.000V with ±2.5% tolerance over temperature (-40°C to +85°C), as defined by the "40" suffix in its part number per Maxim's Threshold Suffix Guide. This value is guaranteed across the full operating range and includes 0.5% hysteresis to prevent chatter near the trip point.

Does the MAX6865UK40D5L+T include a watchdog timer, and what is its timeout?

Yes, the MAX6865UK40D5L+T includes an integrated watchdog timer with a typical timeout of 209s, indicated by the "L" suffix in its part number. The timer resets on any rising or falling edge at the WDI pin and triggers reset if no edge occurs within the timeout window - providing robust firmware hang detection.

What is the reset timeout period for the MAX6865UK40D5L+T, and how is it selected?

The MAX6865UK40D5L+T has a fixed 450ms minimum reset timeout period, specified by the "D5" suffix. This value is factory-programmed and cannot be altered externally - ensuring consistent reset assertion duration across all units for predictable µP initialization timing.

What type of reset output does the MAX6865UK40D5L+T provide?

The MAX6865UK40D5L+T provides an active-high push-pull reset output on Pin 1. It drives high during reset assertion and low during deassertion, eliminating the need for external pull-up resistors and enabling direct connection to µP reset inputs rated for VCC-referenced logic levels.

Is the MAX6865UK40D5L+T compatible with 1.8V, 3.3V, and 5V supply rails?

Yes, the MAX6865UK40D5L+T operates across VCC = 1.1V to 5.5V and monitors its own supply as the supervised rail. Its 4.000V threshold makes it ideal for 5V systems or post-LDO 3.3V rails with margin; its 170nA ICC and 1.1V validity ensure compatibility with ultra-low-voltage energy harvesting designs.