Analog Devices Inc./Maxim Integrated MAX6865UK20D4L+T

Overview

The MAX6865UK20D4L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, a factory-trimmed 2.0V reset threshold (±2.5%), 1200ms minimum reset timeout, manual reset input (MR), and a 209s typical watchdog timeout (L-suffix). It monitors VCC for brownout detection and asserts reset during power-up, power-down, or software lockup in battery-powered medical and portable electronics.

For engineers reviewing the MAX6865UK20D4L+T datasheet, MAX6865UK20D4L+T pinout, MAX6865UK20D4L+T application, or MAX6865UK20D4L+T equivalent, this page delivers verified electrical parameters, functional pin mapping, real-world use cases in glucose monitors and patient monitors, and validated alternative parts with documented timing and output differences.

Technical Context

This device integrates three core functions: precise VCC voltage monitoring with hysteresis (0.5% of VTH), a glitch-immune manual reset input with 250ns MR-to-reset delay and 1µs minimum pulse width, and a watchdog timer that triggers reset if WDI remains static beyond 209s (typ). The internal 10kΩ MR pullup eliminates external components.

Reset assertion is guaranteed valid down to VCC = +1.1V, and the open-drain RESET output supports level-shifting across 0–5.5V logic domains. The watchdog clears on any WDI edge, MR assertion, or active reset - ensuring robust recovery from firmware hangs without requiring CPU intervention.

Key Specifications

Pinout & Package

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

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK20D4L+T, the MAX6865UK20D4L+T offers identical supervision specs but adds WDI functionality; versus TPS3838K20DBVR, it delivers 10× lower ICC and integrated watchdog - making it optimal for long-life, safety-critical portable medical systems.

Availability

MAX6865UK20D4L+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, and MP3 players requiring stable component supply, long-term lifecycle support, and lead-free compliance.

Supply support for MAX6865UK20D4L+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 MAX68xx family delivers nanopower supervisory solutions optimized for battery-constrained portable medical and consumer electronics, emphasizing ultra-low ICC, wide VCC validity, and integrated watchdog reliability.

FAQ

What is the exact reset threshold voltage for MAX6865UK20D4L+T?

The MAX6865UK20D4L+T has a factory-trimmed reset threshold of 2.0V with ±2.5% tolerance over -40°C to +85°C. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "20" corresponds to 2.000V nominal. The device guarantees valid reset assertion down to VCC = +1.1V, supporting robust brownout detection in low-voltage systems.

Does MAX6865UK20D4L+T include a watchdog timer, and what is its timeout?

Yes, the MAX6865UK20D4L+T includes a watchdog timer with a typical timeout of 209 seconds, indicated by the "L" suffix in the part number. This long-duration timeout is designed for low-activity embedded systems such as glucose meters that operate intermittently. The watchdog clears on any rising or falling edge at the WDI pin and triggers reset if WDI remains static beyond the timeout period.

What is the reset timeout period for MAX6865UK20D4L+T, and how is it selected?

The MAX6865UK20D4L+T uses the "D4" suffix to specify a minimum reset timeout period of 1200ms. This value is fixed at manufacture and cannot be altered externally. Unlike the MAX6861–MAX6863 variants, the MAX6865 does not feature a CT pin for dynamic timeout selection - the D4 timing is hard-coded into the silicon and verified per Table 4 (Reset Timeout Periods) in the datasheet.

What package type and pin configuration does MAX6865UK20D4L+T use?

The MAX6865UK20D4L+T is housed in a 5-pin SOT23-5 package with standard pinout: Pin 1 = RESET (open-drain active-low), Pin 2 = GND, Pin 3 = MR (active-low manual reset), Pin 4 = WDI (watchdog input), Pin 5 = VCC. This configuration is explicitly shown in the "MAX6864/MAX6865/MAX6866 Pin Description" section and confirmed in the Pin Configurations diagram on page 15 of the datasheet.

Is MAX6865UK20D4L+T compatible with other MAX68xx supervisory ICs in the same family?

Yes, the MAX6865UK20D4L+T shares the same 5-pin SOT23-5 footprint and core functional architecture with MAX6864–MAX6866 variants. It is pin-compatible with MAX6864UK20D4L+T and MAX6866UK20D4L+T, differing only in RESET output type (open-drain vs. push-pull active-low vs. push-pull active-high). All share identical VTH, tRP, tWD, MR behavior, and thermal specifications across -40°C to +85°C.