Analog Devices Inc./Maxim Integrated MAX6865UK40D3L+T

Overview

MAX6865UK40D3L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, factory-trimmed 4.000V reset threshold (±2.5%), 300ms minimum reset timeout, manual reset input (MR), and watchdog timer with 209s typical timeout. It monitors VCC in battery-powered medical and portable electronics to ensure reliable µP initialization during brownout or software lockup.

For engineers reviewing the MAX6865UK40D3L+T datasheet, MAX6865UK40D3L+T pinout, MAX6865UK40D3L+T application, or MAX6865UK40D3L+T equivalent, this page delivers verified functional specifications, validated pin roles, confirmed reset timing behavior, and real-world design implications for low-power embedded systems requiring guaranteed reset assertion down to VCC = +1.1V.

Technical Context

The MAX6865UK40D3L+T integrates voltage monitoring, a manual reset input (MR), and a watchdog timer that triggers reset if WDI remains static beyond 209s (typ). Its internal reset timeout generator ensures ≥300ms reset pulse after VCC recovery or MR deassertion.

It uses BiCMOS process technology (2848 transistors) and guarantees valid reset output down to VCC = +1.1V. The device is immune to short VCC transients (<40µs at 100mV overdrive) and features internal 10kΩ MR pullup, 150ns WDI pulse detection, and no external components required.

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 TPS3836K33DBVR and STM6315SW33DX6F, the MAX6865UK40D3L+T uniquely combines ultra-low 170nA current, 4.000V precision threshold, integrated watchdog with 209s timeout, and manual reset - making it the only viable choice for long-life, safety-critical portable medical devices requiring full supervision coverage.

Availability

MAX6865UK40D3L+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered IoT sensors, industrial handheld terminals, and wearable health trackers requiring stable component supply across extended product lifecycles.

Supply support for MAX6865UK40D3L+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 demanding industrial, medical, and automotive environments.

The MAX6865UK40D3L+T belongs to the MAX6854–MAX6869 nanopower µP supervisory family, engineered specifically for ultra-low-power battery-operated systems requiring guaranteed reset assertion, manual reset capability, and watchdog protection against firmware faults.

FAQ

What is the exact reset threshold voltage of the MAX6865UK40D3L+T?

The MAX6865UK40D3L+T has a factory-trimmed reset threshold voltage of 4.000V 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 "40" corresponds to 4.000V nominal. The device guarantees valid reset assertion down to VCC = +1.1V, ensuring reliability even during deep brownout conditions.

Does the MAX6865UK40D3L+T include a watchdog timer, and what is its timeout period?

Yes, the MAX6865UK40D3L+T includes a watchdog timer with a typical timeout period of 209s (L suffix), as specified in Table 3 (Watchdog Timeout). 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 integrated - no external components are required to enable watchdog functionality in the MAX6865UK40D3L+T.

What type of reset output does the MAX6865UK40D3L+T provide, and how is it configured?

The MAX6865UK40D3L+T provides an active-high push-pull reset output on Pin 1. Unlike open-drain variants, this configuration drives high actively and does not require an external pullup resistor. The output sources ≥500µA at VCC ≥ 2.38V when deasserted and sinks current during assertion, enabling direct interfacing with µP reset inputs rated for active-high logic levels.

How does the manual reset (MR) input function in the MAX6865UK40D3L+T?

The MR input on Pin 3 of the MAX6865UK40D3L+T is an active-low signal with internal 10kΩ pullup to VCC. Driving MR low initiates a reset that remains asserted for the full 300ms timeout period after MR returns high. The device rejects glitches <200ns and accepts standard CMOS logic levels, eliminating need for external debounce. Leaving MR unconnected defaults to inactive (high) state.

What is the supply current consumption of the MAX6865UK40D3L+T across operating conditions?

The MAX6865UK40D3L+T consumes 170nA typical supply current at +25°C and VCC = 2.5V, rising to ≤400nA at +85°C per Electrical Characteristics table. Current remains stable across VCC = 1.2V to 5.5V and is independent of watchdog activity - unlike competing supervisors, its ICC does not increase with WDI toggling frequency, preserving battery life in always-on applications.