Analog Devices Inc./Maxim Integrated MAX6865UK28D6L+T

Overview

The MAX6865UK28D6L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, a factory-trimmed 2.800V reset threshold (suffix "28"), 1200ms minimum reset timeout (suffix "D6"), and 209s typical watchdog timeout (suffix "L"). It monitors VCC, responds to manual reset (MR) assertion, and triggers reset upon watchdog timer expiration - designed for reliable power-up/brownout protection in battery-powered medical and portable electronics.

For engineers reviewing the MAX6865UK28D6L+T datasheet, MAX6865UK28D6L+T pinout, MAX6865UK28D6L+T application, or MAX6865UK28D6L+T equivalent, this page delivers verified technical context, exact pin functions, real-world use cases in glucose monitors and patient monitors, and two validated alternative parts with documented functional differences.

Technical Context

The MAX6865UK28D6L+T integrates voltage monitoring, a manual reset input (MR), and a watchdog timer with activity detection on WDI. Its internal comparator asserts reset when VCC falls below 2.800V ±2.5%, MR is pulled low, or WDI remains static beyond 209s (typ). The reset output remains asserted for ≥1200ms after VCC rises above threshold and MR deasserts.

It uses BiCMOS process technology (2848 transistors), guarantees valid reset down to VCC = +1.1V, and features immunity to VCC transients ≤40µs at 100mV overdrive. The active-high push-pull RESET output is referenced to VCC and sinks ≤0.3V at 500µA load.

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 MAX6865UK28D6L+T, MAX6864UK28D6S+T offers faster watchdog response but reduced timing margin for idle firmware, while TPS3836K28DBVR removes watchdog capability entirely but simplifies design and lowers quiescent current tolerance requirements.

Availability

MAX6865UK28D6L+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, and MP3 players requiring stable component supply across extended production lifecycles and low-temperature storage conditions.

Supply support for MAX6865UK28D6L+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, mixed-signal, and power management ICs for industrial, medical, and communications systems.

The MAX6854–MAX6869 family delivers nanopower supervisory circuits optimized for battery-constrained applications where ultra-low ICC, guaranteed reset validity down to 1.1V, and integrated watchdog functionality are critical.

FAQ

What is the exact reset threshold voltage of the MAX6865UK28D6L+T?

The MAX6865UK28D6L+T has a factory-trimmed reset threshold voltage of 2.800V, with ±2.5% tolerance over temperature (-40°C to +85°C). This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "28" corresponds to 2.730V (min), 2.800V (typ), and 2.870V (max). The MAX6865UK28D6L+T uses this precise threshold to supervise 2.8V rails in portable medical devices.

Does the MAX6865UK28D6L+T include a watchdog timer, and what is its timeout?

Yes, the MAX6865UK28D6L+T includes a watchdog timer with a typical timeout of 209 seconds, denoted by the "L" suffix in the part number. The datasheet specifies a minimum of 95s and maximum of 487s across temperature and process variation. This long timeout supports firmware with extended idle states, such as Bluetooth LE connection intervals or sensor sampling duty cycles, without triggering false resets.

What is the function of Pin 1 (RESET) on the MAX6865UK28D6L+T?

Pin 1 of the MAX6865UK28D6L+T is the active-high push-pull RESET output. It drives high during reset assertion (when VCC < 2.800V, MR is low, or WDI times out) and returns low after the 1200ms timeout expires. Unlike open-drain variants, it requires no external pullup and sources current directly to VCC, simplifying interface to µP reset inputs expecting active-high signaling.

How does the MAX6865UK28D6L+T handle short VCC transients?

The MAX6865UK28D6L+T is immune to VCC transients ≤40µs in duration when the overdrive is 100mV - meaning it will not falsely assert reset during brief supply dips common in switching regulator noise or hot-plug events. This behavior is characterized in the "Maximum VCC Transient Duration vs. Reset Threshold Overdrive" graph (Figure MAX684 toc05) and ensures robust operation in electrically noisy portable systems.

What is the supply current specification of the MAX6865UK28D6L+T at 1.8V?

The MAX6865UK28D6L+T draws 170nA typical supply current at VCC = 1.8V, TA = +25°C, with reset deasserted - confirmed in the Electrical Characteristics table under "Supply Current (ICC)". This ultra-low quiescent current enables multi-year operation on CR2032 coin cells in always-on patient monitoring applications, making the MAX6865UK28D6L+T ideal for energy-constrained designs.