Analog Devices Inc./Maxim Integrated MAX6869UK18D5S+T

Overview

The MAX6869UK18D5S+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 1.8V reset threshold (±2.5%), 300ms minimum reset timeout (D5), and integrated watchdog timer with 3.3s typical timeout (S suffix). It monitors VCC, responds to manual reset (MR), and asserts reset on voltage drop, MR assertion, or watchdog expiration - ideal for battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6869UK18D5S+T datasheet, MAX6869UK18D5S+T pinout, MAX6869UK18D5S+T application, or MAX6869UK18D5S+T equivalent, this page delivers verified technical context, exact pin functions, real-world timing behavior, and validated alternative options for low-power embedded reset supervision.

Technical Context

The MAX6869UK18D5S+T implements a dual-function supervision architecture: a precision bandgap-based voltage monitor with guaranteed reset validity down to VCC = +1.1V, and an independent watchdog timer that clears on any WDI edge (rising or falling) and expires after 3.3s (typ) if inactive. Its internal 10kΩ MR pullup and glitch rejection (200ns) enable robust manual reset without external components.

This device belongs to the MAX6867–MAX6869 variant group, which places WDI on Pin 1 and RESET on Pin 4 (active-low open-drain or push-pull), distinguishing it from earlier MAX6864–MAX6866 variants. The D5 suffix specifies 300ms minimum reset timeout, and the S suffix confirms 3.3s (typ) watchdog period - both factory-trimmed and temperature-stable per published characterization curves.

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 MAX6867UK18D5S+T, the MAX6869UK18D5S+T provides open-drain flexibility for shared reset buses; versus TPS3808G18DBVR, it delivers 15× lower ICC and integrated hardware watchdog - essential for long-life, safety-critical portable medical use.

Availability

MAX6869UK18D5S+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered wearables, and industrial sensor nodes requiring stable component supply across extended product lifecycles.

Supply support for MAX6869UK18D5S+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 interface applications in industrial, medical, and communications markets.

The MAX6867–MAX6869 family targets ultra-low-power microprocessor supervision in space-constrained, battery-operated systems - emphasizing nanoscale ICC, guaranteed brownout response, and integrated watchdog reliability.

FAQ

What is the exact reset threshold voltage of the MAX6869UK18D5S+T?

The MAX6869UK18D5S+T has a factory-trimmed reset threshold of 1.800V with ±2.5% tolerance over temperature (–40°C to +85°C), as defined by the "18" suffix in the part number and confirmed in Table 2 of the datasheet. This value is laser-trimmed during production and does not require external calibration.

Does the MAX6869UK18D5S+T support open-drain or push-pull RESET output?

The MAX6869UK18D5S+T features an active-low open-drain RESET output (Pin 4), as specified in the MAX6867/MAX6868/MAX6869 pin description section. It requires an external pullup resistor to the target logic rail and supports level-shifting - unlike the push-pull variants (e.g., MAX6867).

What is the watchdog timeout behavior of the MAX6869UK18D5S+T?

The MAX6869UK18D5S+T provides a 3.3s typical watchdog timeout (S suffix), with min/max of 1.5s/7.75s over temperature. The timer clears on any WDI edge (rising or falling) and expires only if WDI remains static longer than the timeout - ensuring robust detection of firmware hangs.

Can the MAX6869UK18D5S+T operate reliably below 1.8V supply?

Yes - the MAX6869UK18D5S+T guarantees valid reset assertion down to VCC = +1.1V, and its 170nA supply current remains stable even at 1.2V (per Electrical Characteristics table). However, RESET output sink capability degrades below 1.1V, so system design must ensure µP reset sampling occurs above this threshold.

How is the 300ms reset timeout (D5) implemented in the MAX6869UK18D5S+T?

The D5 suffix corresponds to a 300ms minimum reset timeout period (tRP), with typical 450ms and max 600ms values across temperature and voltage. This timeout begins after VCC rises above the 1.8V threshold *and* MR is deasserted, and is generated by an internal RC oscillator trimmed at wafer test - no external capacitor required.