Analog Devices Inc./Maxim Integrated MAX6865UK27D2L+T

Overview

The MAX6865UK27D2L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, combining voltage monitoring (reset threshold = +2.700V), manual reset input (MR), and watchdog timer (timeout = 209s typ) with ultra-low 170nA typical supply current. It asserts an active-high push-pull RESET signal during VCC brownout, MR assertion, or watchdog timeout, and holds reset for 40ms minimum after recovery - ideal for battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK27D2L+T datasheet, MAX6865UK27D2L+T pinout, MAX6865UK27D2L+T application, or MAX6865UK27D2L+T equivalent, key selection criteria include its guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients (<40µs at 100mV overdrive), fixed 40ms reset timeout, and compatibility with noisy low-power systems requiring reliable power-on reset and software fault detection.

Technical Context

The MAX6865UK27D2L+T implements a dual-trigger reset architecture: one path responds to VCC falling below +2.700V (±2.5%), the second to MR assertion, and the third to WDI inactivity exceeding 209s (typ). Its internal watchdog timer clears on any WDI edge, MR assertion, or RESET assertion - preventing false timeouts during system initialization or interrupt handling.

This device uses BiCMOS process technology (2848 transistors) and features a 10kΩ internal MR pullup, 150ns minimum WDI pulse width detection, and guaranteed VOL ≤ 0.3V at ISINK = 1.2mA (VCC ≥ 2.38V). The push-pull active-high RESET output is referenced to VCC and remains valid across -40°C to +85°C.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount. Compact footprint (2.9mm × 1.6mm × 1.1mm) optimized for space-constrained portable designs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK27D2L+T and TPS3837K27DBVR, the MAX6865UK27D2L+T uniquely delivers active-high RESET, ultra-low 170nA current, and integrated 209s watchdog - making it optimal for space- and power-constrained medical and portable electronics requiring deterministic reset and firmware supervision.

Availability

MAX6865UK27D2L+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, MP3 players, and cell phone baseband subsystems requiring stable component supply, long-term lifecycle support, and lead-free compliance.

Supply support for MAX6865UK27D2L+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 industrial, medical, and communications applications.

The MAX6865UK27D2L+T belongs to the MAX68xx nanopower supervisory family, engineered specifically for ultra-low-power battery-operated systems requiring reliable power-on reset, brownout protection, and software execution monitoring.

FAQ

What is the exact reset threshold voltage of the MAX6865UK27D2L+T?

The MAX6865UK27D2L+T has a factory-trimmed reset threshold of +2.700V, with tolerance of ±2.5% over -40°C to +85°C. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "27" corresponds to 2.700V nominal. The device guarantees valid reset assertion down to VCC = +1.1V, ensuring robust operation during deep brownout conditions.

Does the MAX6865UK27D2L+T include a watchdog timer, and what is its timeout period?

Yes, the MAX6865UK27D2L+T includes a watchdog timer with a typical timeout period of 209 seconds, indicated by the "L" suffix in the part number. This long-duration timeout is designed for firmware with infrequent execution paths or extended calibration routines. The timer clears on any rising or falling edge at the WDI pin, and its accuracy is specified as 95s (min) to 487s (max) across temperature.

What type of RESET output does the MAX6865UK27D2L+T provide, and how is it configured?

The MAX6865UK27D2L+T provides an active-high push-pull RESET output on Pin 1. Unlike open-drain variants, this configuration requires no external pullup resistor and directly drives µP reset inputs expecting high-active logic. The output is referenced to VCC and guarantees VOH ≥ 0.8 × VCC at ISOURCE = 500µA, supporting reliable interfacing across 1.2V–5.5V supply ranges.

How does the manual reset (MR) input function on the MAX6865UK27D2L+T?

The MR input on Pin 3 is an active-low, internally pulled up (10kΩ) signal that initiates reset when driven low. Reset remains asserted while MR is low and continues for the full 40ms timeout after MR returns high. The device accepts CMOS-level logic or mechanical switch inputs; no external debounce is needed due to 200ns glitch rejection and 250ns MR-to-reset delay specification.

What package and environmental compliance does the MAX6865UK27D2L+T have?

The MAX6865UK27D2L+T is supplied in a RoHS-compliant, lead-free 5-pin SOT23-5 package (2.9mm × 1.6mm × 1.1mm). The "+T" suffix explicitly denotes lead-free packaging per JEDEC J-STD-020. It operates across -40°C to +85°C and is qualified for industrial and medical applications requiring traceable, long-lifecycle components.