Analog Devices Inc./Maxim Integrated MAX6865UK31D2L+T

Overview

MAX6865UK31D2L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, factory-trimmed 3.075V reset threshold (suffix "31"), 40ms minimum reset timeout (suffix "D2"), and 209s typical watchdog timeout (suffix "L"). It monitors VCC, responds to manual reset (MR), and triggers reset on watchdog timeout - designed for battery-critical portable medical and handheld devices.

For engineers reviewing the MAX6865UK31D2L+T datasheet, MAX6865UK31D2L+T pinout, MAX6865UK31D2L+T application, or MAX6865UK31D2L+T equivalent, this page delivers verified functional identity, exact pin roles, confirmed timing parameters, real-world use context, and validated alternative options - all specific to the MAX6865UK31D2L+T variant with 3.075V threshold, 40ms reset timeout, and 209s watchdog period.

Technical Context

The MAX6865UK31D2L+T integrates voltage monitoring, manual reset input (MR), and watchdog timer (WDI) in a single BiCMOS IC. Its reset assertion logic combines three independent triggers: VCC falling below 3.075V ±2.5%, MR pulled low, or WDI inactivity exceeding 209s (typ). The internal reset timeout generator enforces a guaranteed minimum 40ms deassertion hold time after recovery.

It uses push-pull active-high RESET output referenced to VCC, supports operation down to VCC = 1.1V with valid reset signaling, and features 10kΩ internal MR pullup. Immunity to short VCC transients (<40µs at 100mV overdrive) ensures robustness in noisy battery-powered environments.

Key Specifications

Pinout & Package

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

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6865UK31D2L+T, MAX6864UK31D2L+T omits active-high RESET but shares identical threshold, timeout, and watchdog specs; TPS3837K33DBVR trades ultra-low current and watchdog for lower cost and simpler function - making it viable only where firmware hang detection is not required.

Availability

MAX6865UK31D2L+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered handhelds, patient monitors, and low-power consumer electronics requiring stable component supply across extended production lifecycles.

Supply support for MAX6865UK31D2L+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-constrained systems - emphasizing ultra-low ICC, wide VCC range, and integrated watchdog for firmware reliability in portable healthcare and handheld electronics.

FAQ

What is the exact reset threshold voltage of the MAX6865UK31D2L+T?

The MAX6865UK31D2L+T has a factory-trimmed reset threshold voltage of 3.075V, with tolerance of ±2.5% over the -40°C to +85°C temperature range. This value is defined by the "31" suffix in the part number and is confirmed in Table 2 (Threshold Suffix Guide) of the official datasheet. The MAX6865UK31D2L+T maintains this accuracy without external calibration components.

Does the MAX6865UK31D2L+T include a watchdog timer, and what is its timeout period?

Yes, the MAX6865UK31D2L+T includes a 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 applies across the full operating temperature range. The timer resets on any rising or falling edge at the WDI pin and triggers reset if no edge occurs within the timeout window.

What type of RESET output does the MAX6865UK31D2L+T provide?

The MAX6865UK31D2L+T provides a push-pull active-high RESET output, as confirmed by its position in the Selector Guide (row MAX6865) and Pin Description section. Pin 1 drives high during reset assertion and low when deasserted - eliminating need for external pullup resistors and simplifying interface to µPs with active-high reset inputs.

What is the minimum reset timeout period for the MAX6865UK31D2L+T?

The MAX6865UK31D2L+T has a minimum reset timeout period of 40ms, specified by the "D2" suffix per Table 4 (Reset Timeout Periods). This guaranteed minimum ensures sufficient hold time for microprocessor power-up stabilization and clock initialization before release - critical for reliable boot in portable systems.

Is the MAX6865UK31D2L+T compatible with 1.8V or 2.5V supply rails?

Yes, the MAX6865UK31D2L+T operates across VCC = 1.2V to 5.5V and guarantees valid reset signaling down to VCC = 1.1V. Its 3.075V threshold is optimized for 3.3V systems, but the device functions correctly as a supervisor for 1.8V or 2.5V rails when used with appropriate external logic-level translation - confirmed in Electrical Characteristics and Typical Operating Characteristics sections.