Analog Devices Inc./Maxim Integrated MAX6865UK31D6S+T

Overview

The MAX6865UK31D6S+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, combining voltage monitoring (3.075V factory-trimmed reset threshold), manual reset input (MR), and watchdog timer (209s typical timeout) with ultra-low 170nA typical supply current. It asserts an active-high push-pull RESET output during VCC brownout, MR assertion, or watchdog timeout, and holds reset for 600–1200ms after recovery - ideal for battery-powered glucose monitors and portable medical devices requiring guaranteed reset validity down to VCC = +1.1V.

For engineers reviewing the MAX6865UK31D6S+T datasheet, MAX6865UK31D6S+T pinout, MAX6865UK31D6S+T application, or MAX6865UK31D6S+T equivalent, key selection criteria include its 3.075V reset threshold tolerance (±2.5%), 209s watchdog timeout option (L-suffix), D6 reset timeout (600–1200ms), active-high push-pull output, and immunity to sub-40µs VCC transients at 100mV overdrive.

Technical Context

This device implements a dual-trigger reset architecture: one path responds to VCC falling below 3.075V (with 0.5% hysteresis), while a second path activates on MR low or WDI inactivity exceeding 209s (typ). The internal watchdog timer clears on any WDI edge, MR assertion, or RESET assertion - ensuring robust detection of software hangs without false triggers from brief glitches.

Its BiCMOS process enables guaranteed operation from VCC = 1.2V to 5.5V, with RESET output valid to VCC = +1.1V and VOL ≤ 0.3V at ISINK = 1.2mA (VCC ≥ 2.38V). The 10kΩ internal MR pullup eliminates external components, and the absence of external timing capacitors supports true "no-component" integration in space-constrained portable designs.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free (RoHS-compliant), 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 MAX6864UK31D6S+T, the MAX6865UK31D6S+T adds essential watchdog supervision for autonomous firmware recovery; compared with TPS3837K33DBVR, it delivers 147× lower ICC and 3× longer reset timeout - directly enabling multi-year battery operation in medical wearables.

Availability

MAX6865UK31D6S+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign recorders, industrial handheld scanners, and wearable health trackers requiring stable component supply across extended production lifecycles.

Supply support for MAX6865UK31D6S+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 demanding industrial, medical, and communications applications.

The MAX6854–MAX6869 family was engineered specifically for ultra-low-power microprocessor supervision in battery-constrained portable medical and consumer electronics - prioritizing nanoscale ICC, guaranteed low-VCC operation, and integrated watchdog safety.

FAQ

What is the exact reset threshold voltage of the MAX6865UK31D6S+T?

The MAX6865UK31D6S+T features a factory-trimmed reset threshold of 3.075V, with ±2.5% tolerance over temperature (-40°C to +85°C). This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "31" corresponds to 3.075V nominal. The device guarantees valid reset assertion down to VCC = +1.1V, making it suitable for brownout detection in 3.3V systems with significant rail droop.

Does the MAX6865UK31D6S+T include a watchdog timer, and what is its timeout period?

Yes, the MAX6865UK31D6S+T includes a watchdog timer with a typical timeout period 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 that "L" corresponds to 95–487s (min–max) with 209s typical. The timer resets on any rising or falling edge at the WDI pin and expires only if WDI remains static beyond this interval.

What does the "D6" in MAX6865UK31D6S+T signify?

The "D6" in MAX6865UK31D6S+T denotes the reset timeout period option: 600–1200ms (minimum–maximum), with 900ms typical. As defined in Table 4 (Reset Timeout Periods), D6 provides the longest standard timeout in the family, ensuring sufficient hold time for complex microprocessor initialization sequences, including flash programming and peripheral configuration, before releasing the RESET signal.

Is the RESET output of the MAX6865UK31D6S+T push-pull or open-drain, and is it active-high or active-low?

The MAX6865UK31D6S+T features an active-high push-pull RESET output, confirmed by its position in the Selector Guide (row MAX6865, column "Push-Pull Active High") and Pin Description (Pin 1 function for MAX6865: "Active-High Push-Pull Reset Output"). This eliminates the need for an external pullup resistor and ensures fast, rail-referenced logic-level drive compatible with standard µP reset inputs requiring high-voltage assertion.

What package type and environmental compliance does the MAX6865UK31D6S+T use?

The MAX6865UK31D6S+T is supplied in a 5-pin SOT23-5 package with lead-free (RoHS-compliant) termination, as indicated by the "+T" suffix per Maxim's ordering convention. The package dimensions and thermal characteristics match standard SOT23 footprints, enabling drop-in compatibility with existing layouts. Absolute maximum ratings confirm operation up to +150°C junction temperature, supporting reflow soldering per JEDEC J-STD-020.