Analog Devices Inc./Maxim Integrated MAX6865UK24D2L+T

Overview

The MAX6865UK24D2L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, factory-trimmed 2.4V reset threshold (±2.5%), 40ms minimum reset timeout, and integrated watchdog timer with 209s typical timeout. It monitors VCC, responds to manual reset (MR), and asserts active-high push-pull RESET during brownout, power-up, or watchdog expiration - used in battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK24D2L+T datasheet, MAX6865UK24D2L+T pinout, MAX6865UK24D2L+T application, or MAX6865UK24D2L+T equivalent, key selection criteria include its 2.4V VTH tolerance, 40ms tRP timing, 209s watchdog period, push-pull active-high RESET output, and guaranteed operation down to VCC = 1.1V - all critical for low-power embedded system reliability.

Technical Context

This device implements a precision voltage monitor with hysteresis (0.5% of VTH), a digital watchdog timer cleared by WDI edges, and a fixed 40ms reset timeout after VCC recovery or MR deassertion. Its BiCMOS process enables stable operation across -40°C to +85°C while maintaining sub-µA quiescent current.

The internal 10kΩ MR pullup, glitch-immune MR input (200ns rejection), and WDI pulse-width tolerance (≥150ns) ensure robust reset initiation in noisy environments. RESET remains valid down to VCC = 1.1V, and VOH meets 0.8×VCC at ISOURCE = 500µA - enabling direct interfacing with 1.8V/2.5V/3.3V µP reset inputs.

Key Specifications

Pinout & Package

Package: 5-pin SOT23 (lead-free, +T suffix), footprint-compatible with industry-standard 5-lead SOT-23 packages.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK24D2L+T and TPS3837K24DBVR, the MAX6865UK24D2L+T uniquely delivers active-high push-pull RESET, 209s watchdog, and 170nA ICC in one 5-pin SOT23 - eliminating external components and enabling longest battery life in supervised medical wearables.

Availability

MAX6865UK24D2L+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign recorders, and wireless telemetry devices requiring stable component supply with long-term lifecycle support.

Supply support for MAX6865UK24D2L+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 communications markets.

The MAX6854–MAX6869 family was engineered specifically for ultra-low-power microprocessor supervision in battery-critical portable medical and handheld electronics - prioritizing nanoscale ICC, guaranteed VCC = 1.1V operation, and integrated watchdog safety.

FAQ

What is the exact reset threshold voltage of the MAX6865UK24D2L+T?

The MAX6865UK24D2L+T has a factory-trimmed reset threshold of 2.4V with ±2.5% tolerance over -40°C to +85°C. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "24" corresponds to VTH = 2.4V nominal. The device guarantees valid reset assertion down to VCC = 1.1V, making it suitable for deep brownout detection in low-voltage battery systems.

Does the MAX6865UK24D2L+T include a watchdog timer, and what is its timeout period?

Yes, the MAX6865UK24D2L+T includes an integrated watchdog timer with a typical timeout period of 209 seconds, indicated by the "L" suffix in the part number. This is verified in Table 3 (Watchdog Timeout) and the Ordering Information section. The timer resets on any rising or falling edge at the WDI pin and expires only if WDI remains static beyond 209s - providing long-duration firmware supervision ideal for infrequently active medical sensors.

What type of RESET output does the MAX6865UK24D2L+T provide, and how is it configured?

The MAX6865UK24D2L+T provides a push-pull active-high RESET output, confirmed by its position in the Selector Guide (row MAX6865, column "Push-Pull ACTIVE HIGH") and Pin Description table. Unlike open-drain variants, it requires no external pullup and directly drives high during reset assertion. VOH meets 0.8×VCC at 500µA source current, ensuring compatibility with standard µP reset inputs across 1.8V–3.3V logic families.

What is the minimum reset timeout period for the MAX6865UK24D2L+T, and how is it selected?

The MAX6865UK24D2L+T has a fixed minimum reset timeout period of 40ms, denoted by the "D2" suffix per Table 4 (Reset Timeout Periods). This value is factory-programmed and not user-selectable - unlike MAX6861–MAX6863 which use the CT pin for selection. The 40ms tRP ensures sufficient hold time for power supply stabilization and µP internal clock startup before release from reset.

How does the manual reset (MR) input function on the MAX6865UK24D2L+T?

The MR input on the MAX6865UK24D2L+T is an active-low signal with internal 10kΩ pullup to VCC. Driving MR low initiates reset immediately, and RESET remains asserted for the full 40ms timeout after MR returns high. It rejects glitches ≤200ns and accepts CMOS-level signals - enabling direct connection to momentary switches or GPIOs without external debounce. Leaving MR unconnected defaults to inactive (pulled high).