Analog Devices Inc./Maxim Integrated MAX6865UK27D1S+T

Overview

MAX6865UK27D1S+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, factory-trimmed 2.7V reset threshold (±2.5%), 10ms minimum reset timeout, manual reset input (MR), and watchdog timer with 3.3s 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 MAX6865UK27D1S+T datasheet, MAX6865UK27D1S+T pinout, MAX6865UK27D1S+T application, or MAX6865UK27D1S+T equivalent, key selection criteria include guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients (<40µs at 100mV overdrive), push-pull active-high RESET output, and compatibility with noisy low-power systems requiring minimal quiescent current.

Technical Context

The MAX6865UK27D1S+T integrates voltage monitoring, manual reset assertion, and watchdog timer functionality in a single BiCMOS IC. Its reset logic asserts RESET when VCC falls below 2.7V, MR is pulled low, or WDI remains static beyond 3.3s - with internal timing controlled by precision on-chip RC networks.

It features a dedicated WDI input that clears the watchdog timer on any rising or falling edge, and a push-pull active-high RESET output referenced to VCC. The device operates across -40°C to +85°C and guarantees valid reset signaling even as VCC drops to 1.1V, enabling robust operation in deep-brownout conditions.

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 TPS3837K27DBVR and MAX6316LUK27D3+T, the MAX6865UK27D1S+T uniquely combines 2.7V supervision, 10ms reset, active-high push-pull output, and integrated watchdog - making it optimal for compact, safety-critical portable devices needing both power and software fault detection.

Availability

MAX6865UK27D1S+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, MP3 players, and feature cell phones requiring stable component supply across industrial temperature ranges and long production lifecycles.

Supply support for MAX6865UK27D1S+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 connectivity in resource-constrained systems.

The MAX6854–MAX6869 family delivers nanopower supervision for battery-operated medical, portable, and IoT endpoints - prioritizing ultra-low ICC, guaranteed low-VCC operation, and integrated watchdog reliability.

FAQ

What is the reset threshold voltage of the MAX6865UK27D1S+T?

The MAX6865UK27D1S+T has a factory-trimmed reset threshold of 2.7V with ±2.5% tolerance over -40°C to +85°C. This value is encoded in the "27" suffix per Maxim's Threshold Suffix Guide (Table 2), and is guaranteed to remain stable across temperature and supply variations, ensuring consistent brownout detection for 2.7V rails.

Does the MAX6865UK27D1S+T include a watchdog timer, and what is its timeout?

Yes, the MAX6865UK27D1S+T includes an integrated watchdog timer with a typical timeout of 3.3s (suffix "S"), as confirmed by the "S" in its order code. The timer resets on any WDI edge and expires only if WDI remains static beyond this period - providing reliable firmware lockup detection without external components.

What type of RESET output does the MAX6865UK27D1S+T provide?

The MAX6865UK27D1S+T provides a push-pull active-high RESET output (Pin 1), meaning it drives high during reset assertion and low when deasserted. This eliminates the need for an external pullup resistor and simplifies interfacing with µPs that require active-high reset signals, such as many ARM and Renesas MCUs.

What is the minimum reset timeout period for the MAX6865UK27D1S+T?

The MAX6865UK27D1S+T has a minimum reset timeout period of 10ms, indicated by the "D1" suffix in its part number. This value is guaranteed across temperature and supply voltage, ensuring sufficient pulse width to meet the reset hold-time requirements of modern low-power microcontrollers.

Is the MAX6865UK27D1S+T compatible with noisy, low-voltage battery systems?

Yes, the MAX6865UK27D1S+T is specifically designed for such environments: it guarantees valid reset operation down to VCC = +1.1V, tolerates VCC transients ≤40µs at 100mV overdrive, draws only 170nA typical supply current, and includes internal MR pullup and WDI edge sensitivity - all critical for reliable operation in coin-cell or single-Li-ion powered devices.