Analog Devices Inc./Maxim Integrated MAX6865UK18D1L+T

Overview

The MAX6865UK18D1L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, combining voltage monitoring (1.8V reset threshold), manual reset input (MR), and watchdog timer (209s typical timeout) with ultra-low 170nA supply current. It asserts an active-high push-pull RESET output during VCC brownout, MR assertion, or watchdog timeout, ensuring reliable µP initialization in battery-powered medical and portable systems.

For engineers reviewing the MAX6865UK18D1L+T datasheet, MAX6865UK18D1L+T pinout, MAX6865UK18D1L+T application, or MAX6865UK18D1L+T equivalent, this device serves as a low-power, single-supply reset supervisor with integrated watchdog for safety-critical embedded control where supply current, reset validity down to 1.1V, and transient immunity are design-critical.

Technical Context

The MAX6865UK18D1L+T implements a precision bandgap-based voltage monitor with factory-trimmed 1.800V ±2.5% reset threshold and guaranteed reset validity down to VCC = 1.1V. Its watchdog timer monitors WDI activity with 209s typical timeout (L-suffix), clearing on any edge transition and disabling during RESET assertion.

This device features a push-pull active-high RESET output referenced to VCC, internal 10kΩ MR pullup, and no external components required. It operates across -40°C to +85°C and draws only 170nA typical supply current at VCC = 1.8V, enabling multi-year operation on coin-cell batteries.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount. Compact 2.9mm × 1.6mm footprint ideal 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 MAX6864UK18D1L+T and TPS3836K33DBVR, the MAX6865UK18D1L+T uniquely delivers active-high RESET, 170nA current, and integrated watchdog-enabling compact, long-life medical designs where reset polarity and power efficiency are non-negotiable.

Availability

MAX6865UK18D1L+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign equipment, and wireless telemetry devices requiring stable component supply, long-term lifecycle support, and lead-free compliance.

Supply support for MAX6865UK18D1L+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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, medical, and communications markets.

The MAX6865UK18D1L+T belongs to the MAX68xx nanopower supervisory family, designed specifically for ultra-low-power, safety-critical portable medical and battery-operated embedded systems demanding guaranteed reset behavior and long service life.

FAQ

What is the reset threshold voltage of the MAX6865UK18D1L+T?

The MAX6865UK18D1L+T has a factory-trimmed reset threshold of 1.800V 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 "18" corresponds to 1.800V nominal. The device guarantees valid reset assertion down to VCC = 1.1V, making it suitable for brownout detection in low-voltage systems.

Does the MAX6865UK18D1L+T include a watchdog timer, and what is its timeout?

Yes, the MAX6865UK18D1L+T includes a watchdog timer with a typical timeout of 209 seconds, indicated by the "L" suffix in the part number. This is verified in Table 3 (Watchdog Timeout) and the Ordering Information section, which specifies "L" as 95s/209s/487s (min/typ/max). The timer clears on any rising or falling edge at the WDI pin and remains disabled while RESET is asserted.

What type of reset output does the MAX6865UK18D1L+T provide?

The MAX6865UK18D1L+T provides an active-high push-pull RESET output, as confirmed by the Pin Description for MAX6865 (page 8) and Selector Guide (page 16). Unlike open-drain variants, this output requires no external pullup resistor and drives high to VCC when deasserted, simplifying interface to µPs with active-high reset inputs.

What is the minimum reset timeout period for the MAX6865UK18D1L+T?

The MAX6865UK18D1L+T has a minimum reset timeout period of 10ms, denoted by the "D1" suffix in the part number. This is specified in Table 4 (Reset Timeout Periods) as D1 = 10/15/25ms (min/typ/max). The timeout begins after VCC rises above the reset threshold and MR is deasserted, ensuring sufficient hold time for µP initialization.

How does the MAX6865UK18D1L+T handle manual reset input (MR)?

The MAX6865UK18D1L+T features an active-low MR input with internal 10kΩ pullup to VCC, as documented in the Pin Description (page 8) and Applications Information (page 11). Driving MR low initiates a reset that persists for the full timeout period (10ms min) after MR returns high. MR accepts CMOS logic levels and supports direct connection to momentary switches without external debounce circuitry.