Analog Devices Inc./Maxim Integrated MAX6869UK31D3S+T

Overview

MAX6869UK31D3S+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, factory-trimmed 3.075V reset threshold (suffix "31"), 150ms minimum reset timeout (suffix "D3"), and 209s typical watchdog timeout (suffix "S"). It monitors VCC, responds to manual reset (MR), and triggers reset on watchdog timeout - designed for battery-critical systems like glucose monitors and portable medical devices.

For engineers reviewing the MAX6869UK31D3S+T datasheet, MAX6869UK31D3S+T pinout, MAX6869UK31D3S+T application, or MAX6869UK31D3S+T equivalent, this page delivers verified functional identity, exact reset timing values, watchdog behavior under voltage transients, and validated alternative options for low-power µP supervision with manual reset and watchdog capability.

Technical Context

The MAX6869UK31D3S+T implements a dual-trigger reset architecture: it asserts reset when VCC falls below 3.075V (±2.5%), when MR is pulled low, or when WDI remains static beyond 209s (typ). Its internal watchdog timer clears on any WDI edge, MR assertion, or active reset - ensuring robust detection of firmware hangs without false triggers from noise.

Reset deassertion follows a guaranteed 150ms (min) timeout after VCC rises above threshold and MR is released; the output remains valid down to VCC = 1.1V, and the device is immune to VCC transients ≤40µs at 100mV overdrive. All logic inputs (MR, WDI) accept standard CMOS thresholds (VIH = 0.7×VCC, VIL = 0.3×VCC).

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, -40°C to +85°C operating range.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6869UK31D3S+T, MAX6864UK31D3S+T offers identical supervision specs but requires pin reassignment, while TPS3838K33DBVR trades 9× higher current and no watchdog for broader distributor availability and simpler qualification.

Availability

MAX6869UK31D3S+T is available at Aetrix Electronics and suitable for glucose monitors, patient loggers, portable ultrasound probes, and handheld drug infusion pumps requiring stable component supply across extended product lifecycles.

Supply support for MAX6869UK31D3S+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 MAX6854–MAX6869 family delivers nanopower supervision for battery-constrained systems, with integrated watchdog, manual reset, and factory-trimmed thresholds to eliminate calibration overhead in portable medical and IoT endpoints.

FAQ

What is the exact reset threshold voltage of MAX6869UK31D3S+T?

The MAX6869UK31D3S+T has a factory-trimmed reset threshold of 3.075V, with ±2.5% tolerance over -40°C to +85°C. This value is confirmed by the "31" suffix in the part number per Table 2 of the datasheet and is measured at VCC falling edge. The MAX6869UK31D3S+T maintains this accuracy without external calibration, making it suitable for 3.3V rail supervision with defined brownout margins.

Does MAX6869UK31D3S+T support open-drain or push-pull reset output?

The MAX6869UK31D3S+T features an active-low open-drain RESET output (pin 4), requiring an external pullup resistor. This is confirmed by its position in the Selector Guide (row MAX6869, column "Open-Drain Active Low") and Pin Description (page 9). Unlike MAX6864 variants, the MAX6869UK31D3S+T does not offer push-pull output - using open-drain enables level-shifting to different logic families and simplifies wired-OR reset bus configurations.

What is the watchdog timeout period for MAX6869UK31D3S+T?

The MAX6869UK31D3S+T provides a 209s typical watchdog timeout period, designated by the "S" suffix per Table 3. This value is specified at TA = +25°C and varies from 95s (min) to 487s (max) over temperature. The MAX6869UK31D3S+T watchdog timer resets on any WDI edge, MR assertion, or active reset - ensuring reliable detection of firmware stalls in long-interval applications like environmental data loggers.

Can MAX6869UK31D3S+T operate with VCC below 1.5V?

Yes, the MAX6869UK31D3S+T guarantees valid reset assertion down to VCC = 1.1V, as stated in the Absolute Maximum Ratings and Electrical Characteristics tables. At VCC = 1.2V, supply current remains at 190nA (typ), and RESET output sinks ≥50µA with VOL ≤0.3V. This capability allows the MAX6869UK31D3S+T to maintain supervision integrity during deep brownout events that would disable most competing supervisors.

How is the reset timeout period configured on MAX6869UK31D3S+T?

MAX6869UK31D3S+T uses a fixed 150ms minimum reset timeout period, indicated by the "D3" suffix per Table 4. Unlike MAX6861–MAX6863 variants, it has no CT pin for dynamic selection - the timeout is factory-set and unchangeable. This simplifies design by eliminating configuration resistors or firmware dependencies, and ensures consistent reset hold time across all units of MAX6869UK31D3S+T in production.