Analog Devices Inc./Maxim Integrated MAX6865UK44D3L+T

Overview

The MAX6865UK44D3L+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 4.266V to 4.484V reset threshold (suffix "44"), 150ms minimum reset timeout (D3), and a 209s typical watchdog timeout (L suffix). It monitors VCC, responds to manual reset (MR) assertion, and triggers reset upon watchdog timer expiration - ideal for battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK44D3L+T datasheet, MAX6865UK44D3L+T pinout, MAX6865UK44D3L+T application, or MAX6865UK44D3L+T equivalent, key selection criteria include its guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients (<40µs at 100mV overdrive), push-pull active-high RESET output, and compatibility with noisy low-power systems requiring deterministic reset timing and watchdog supervision.

Technical Context

This device integrates three core functions: precision voltage monitoring with ±2.5% threshold accuracy over temperature, a manual reset input with 250ns MR-to-reset delay and internal 10kΩ pullup, and a watchdog timer that clears on any WDI edge and expires if WDI remains static beyond 209s (typ). Its BiCMOS process enables stable operation from 1.2V to 5.5V supply.

The MAX6865UK44D3L+T implements a fixed 150ms minimum reset timeout after VCC recovery or MR deassertion, and guarantees RESET output validity down to VCC = +1.1V - critical for brownout detection in sub-1.8V logic domains. The active-high push-pull RESET output sources ≥0.8×VCC at 500µA when deasserted and sinks ≤0.3V at 1.2mA when asserted.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount, footprint-compatible with industry-standard 5-pin SOT23 supervisors.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK44D3L+T and TPS3838K33DBVR, the MAX6865UK44D3L+T uniquely delivers active-high push-pull RESET, 209s watchdog supervision, and 170nA ICC in one 5-pin SOT23 - enabling compact, ultra-low-power, fail-safe reset architecture without design compromises.

Availability

MAX6865UK44D3L+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign recorders, industrial handheld scanners, and low-power IoT edge sensors requiring stable component supply across extended product lifecycles.

Supply support for MAX6865UK44D3L+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 healthcare, industrial, and communications markets.

The MAX6854–MAX6869 family was engineered specifically for ultra-low-power microprocessor supervision in battery-critical medical and portable electronics - prioritizing nanoscale current, robust reset timing, and integrated watchdog reliability.

FAQ

What is the exact reset threshold voltage range for MAX6865UK44D3L+T?

The MAX6865UK44D3L+T has a factory-trimmed reset threshold of 4.266V (min) to 4.484V (max), corresponding to the "44" suffix per Maxim's Threshold Suffix Guide. This 4.375V nominal threshold is optimized for monitoring 4.5V system rails with ±2.5% accuracy over -40°C to +85°C, ensuring reliable detection of brownout conditions without false triggering.

Does MAX6865UK44D3L+T support active-high reset output?

Yes, the MAX6865UK44D3L+T features a push-pull active-high RESET output - Pin 1 drives high during reset assertion and low when deasserted. Unlike open-drain variants, it requires no external pullup resistor and directly interfaces with µPs that accept active-high reset inputs, simplifying PCB layout and reducing component count.

What is the watchdog timeout behavior of MAX6865UK44D3L+T?

The MAX6865UK44D3L+T implements a 209s typical watchdog timeout (L-suffix), with min/max of 95s/487s. The internal timer clears on any rising or falling edge at WDI (Pin 4) and expires only if WDI remains static beyond this period - making it suitable for long-cycle firmware tasks in medical telemetry applications where frequent watchdog kicks are impractical.

Can MAX6865UK44D3L+T operate reliably below 1.8V?

Yes, the MAX6865UK44D3L+T guarantees full functionality from VCC = 1.2V to 5.5V and maintains valid RESET assertion down to VCC = +1.1V. Its 170nA typical supply current at 1.8V and stable threshold accuracy across this range make it suitable for Li-ion battery discharge profiles and ultra-low-voltage microcontrollers.

How does the manual reset (MR) input function on MAX6865UK44D3L+T?

The MR input (Pin 3) is active-low with an internal 10kΩ pullup to VCC. Driving MR low initiates reset immediately; RESET remains asserted for the full 150ms (min) timeout after MR returns high. It accepts CMOS logic levels, rejects <200ns glitches, and responds within 250ns - enabling reliable pushbutton reset without external debounce circuitry.