Analog Devices Inc./Maxim Integrated MAX6865UK46D1L+T

Overview

The MAX6865UK46D1L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, factory-trimmed 4.625V reset threshold (±2.5%), 10ms minimum reset timeout, manual reset input (MR), and watchdog timer with 209s typical timeout. It monitors VCC in battery-powered portable electronics to ensure reliable power-on reset and fault recovery.

For engineers reviewing the MAX6865UK46D1L+T datasheet, MAX6865UK46D1L+T pinout, MAX6865UK46D1L+T application, or MAX6865UK46D1L+T equivalent, this device serves as a low-power, single-supply voltage monitor with integrated watchdog and MR functionality - critical for portable medical devices, wearables, and energy-constrained embedded systems where supply current and brownout immunity are design-critical.

Technical Context

This device implements a precision bandgap-based voltage comparator for VCC monitoring, a digital watchdog timer that clears on WDI edge transitions, and an internal 10kΩ MR pullup. The reset assertion logic combines three independent triggers: VCC falling below 4.625V, MR low, or WDI timeout exceeding 209s (typ).

Reset deassertion follows a fixed 10ms timeout after both VCC rises above threshold and MR deasserts; the watchdog timeout is factory-set to L-suffix (209s typ) and immune to short VCC transients ≤40µs at 100mV overdrive. Guaranteed operation down to VCC = 1.1V ensures validity during deep brownout conditions.

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 MAX6864UK46D1L+T, the MAX6865UK46D1L+T offers push-pull active-high RESET for direct µP interface without pullup, while TPS3836K33DBVR trades watchdog capability and ultra-low current for cost reduction in static power-rail monitoring.

Availability

MAX6865UK46D1L+T is available at Aetrix Electronics and suitable for portable medical devices, wearable health monitors, industrial handheld terminals, and low-power IoT sensors requiring stable component supply across extended temperature ranges and long product lifecycles.

Supply support for MAX6865UK46D1L+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 demanding industrial, medical, and communications applications.

The MAX6854–MAX6869 family delivers nanopower supervisory functions targeting battery-operated portable equipment where ultra-low ICC, guaranteed brownout response, and integrated watchdog reliability are essential.

FAQ

What is the exact reset threshold voltage of the MAX6865UK46D1L+T?

The MAX6865UK46D1L+T has a factory-trimmed reset threshold of 4.625V, 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 '46' corresponds to 4.625V nominal. The device guarantees valid reset assertion down to VCC = 1.1V, making it suitable for systems with tight dropout margins.

Does the MAX6865UK46D1L+T include a watchdog timer, and what is its timeout period?

Yes, the MAX6865UK46D1L+T includes a watchdog timer with a typical timeout period of 209s, indicated by the 'L' suffix in the part number. This is verified in Table 3 (Watchdog Timeout) and the Ordering Information section. The timer clears on any rising or falling edge at the WDI pin and expires only if WDI remains static beyond this period - ideal for long-interval firmware supervision.

What type of reset output does the MAX6865UK46D1L+T provide, and how is it configured?

The MAX6865UK46D1L+T provides an active-high push-pull RESET output on Pin 1. Unlike open-drain variants, it drives high to VCC and low to GND without requiring an external pullup resistor. This configuration is confirmed in the MAX6864/MAX6865/MAX6866 Pin Description table and Functional Diagram, where MAX6865 is explicitly designated for active-high push-pull operation.

What is the minimum reset timeout period for the MAX6865UK46D1L+T, and how is it selected?

The MAX6865UK46D1L+T has a fixed minimum reset timeout period of 10ms, denoted by the 'D1' suffix in the part number. This value is specified in Table 4 (Reset Timeout Periods) and applies unconditionally - no external components or pin strapping is needed. The 10ms duration ensures sufficient hold time for most modern µPs while minimizing boot delay in responsive systems.

How does the MAX6865UK46D1L+T handle manual reset input (MR), and what is its internal configuration?

The MAX6865UK46D1L+T features an active-low MR input on Pin 3, internally pulled up to VCC with a 10kΩ resistor. Driving MR low asserts reset immediately, and the output remains asserted for the full 10ms timeout after MR returns high. This behavior is documented in the Pin Description and Detailed Description sections, and eliminates need for external pullup in switch-based reset implementations.