Analog Devices Inc./Maxim Integrated MAX6865UK18D3L+T

Overview

The MAX6865UK18D3L+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 1.8V reset threshold (±2.5%), 300ms minimum reset timeout (D3), and integrated watchdog timer with 209s typical timeout (L suffix). It monitors VCC, responds to manual reset (MR), and triggers reset on watchdog expiration - ideal for battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK18D3L+T datasheet, MAX6865UK18D3L+T pinout, MAX6865UK18D3L+T application, or MAX6865UK18D3L+T equivalent, this device delivers guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients, and push-pull active-high RESET output - critical for reliable power-up sequencing and brownout recovery in low-voltage embedded systems.

Technical Context

The MAX6865UK18D3L+T implements a dual-monitoring architecture: a precision voltage detector with hysteresis (0.5% of VTH) and a watchdog timer that clears on any WDI edge (rising or falling) and expires if WDI remains static beyond 209s (typ). Its internal 10kΩ MR pullup enables direct switch interfacing without external components.

It uses BiCMOS process technology (2848 transistors) to achieve nanoscale quiescent current while maintaining robust noise immunity - evidenced by guaranteed operation under 40µs VCC transients at 100mV overdrive and validated reset timing across –40°C to +85°C.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free (RoHS-compliant), footprint-compatible with industry-standard 5-lead SOT23 layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK18D3S+T and TPS3837K18DBVR, the MAX6865UK18D3L+T uniquely balances ultra-low power, long watchdog timeout, and guaranteed 1.1V reset validity - making it optimal for safety-critical, battery-constrained medical and industrial edge devices where both longevity and fault coverage are mandatory.

Availability

MAX6865UK18D3L+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, MP3 players, and industrial handheld terminals requiring stable component supply and long-term lifecycle support.

Supply support for MAX6865UK18D3L+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, sensing, and interface applications - with emphasis on performance, integration, and reliability.

The MAX6854–MAX6869 family was engineered specifically for ultra-low-power microprocessor supervision in portable and medical electronics, combining voltage monitoring, manual reset, and configurable watchdog functionality in minimal footprint.

FAQ

What is the reset threshold voltage of the MAX6865UK18D3L+T?

The MAX6865UK18D3L+T has a factory-trimmed reset threshold of 1.800V with ±2.5% tolerance over temperature. This value is fixed per the "18" suffix in the part number and is guaranteed valid from –40°C to +85°C. The device asserts reset when VCC falls below this threshold and holds reset for the full 300ms timeout after VCC recovers above it.

Does the MAX6865UK18D3L+T include a watchdog timer, and what is its timeout?

Yes, the MAX6865UK18D3L+T includes a watchdog timer with a typical timeout of 209 seconds, indicated by the "L" suffix. The timer resets on any rising or falling edge at the WDI pin and expires only if WDI remains static beyond this period. It is fully functional across the full operating temperature range and does not require external components.

What type of reset output does the MAX6865UK18D3L+T provide?

The MAX6865UK18D3L+T provides a push-pull active-high RESET output (Pin 1). When asserted, RESET drives high to VCC; when deasserted, it drives low. This eliminates the need for an external pullup resistor and ensures clean, rail-to-rail logic levels compatible with standard µP reset inputs.

How does the MAX6865UK18D3L+T handle short VCC transients?

The MAX6865UK18D3L+T is immune to VCC transients ≤40µs in duration when the overdrive is 100mV - meaning it will not falsely trigger reset during brief supply glitches. This immunity is inherent to its internal design and requires no external filtering, simplifying layout in electrically noisy environments like motor-driven or RF-intensive systems.

What is the supply current of the MAX6865UK18D3L+T at 1.8V?

The MAX6865UK18D3L+T draws 170nA typical supply current at VCC = 1.8V and TA = +25°C, with a maximum of 370nA. This ultralow ICC enables multi-year operation from coin-cell batteries and is a defining feature of the MAX6865UK18D3L+T within the nanopower supervisory category.