Analog Devices Inc./Maxim Integrated MAX6865UK31D3S+T

Overview

The MAX6865UK31D3S+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 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 watchdog timer with 3.3s typical timeout (suffix "S"). It monitors VCC, responds to manual reset (MR), and triggers reset on watchdog expiration - designed for battery-powered medical and portable electronics requiring guaranteed reset validity down to VCC = +1.1V.

For engineers reviewing the MAX6865UK31D3S+T datasheet, MAX6865UK31D3S+T pinout, MAX6865UK31D3S+T application, or MAX6865UK31D3S+T equivalent, this page delivers verified functional identity, exact pin roles, confirmed reset/watchdog timing behavior, real-world application constraints, and validated alternative options - all grounded in Maxim's official documentation for the precise part number.

Technical Context

The MAX6865UK31D3S+T integrates voltage monitoring, manual reset input (MR), and watchdog timer (WDI) in a single BiCMOS IC. Its reset assertion logic combines three independent triggers: VCC falling below 3.075V ±2.5%, MR pulled low, or WDI inactivity exceeding 3.3s (typ). The internal reset timeout generator enforces a guaranteed minimum 150ms deassertion delay after recovery.

It uses a push-pull active-high RESET output referenced to VCC, with VOH ≥ 0.8×VCC at ISOURCE = 500µA and VOL ≤ 0.3V at ISINK = 1.2mA. Immunity to short VCC transients (<40µs at 100mV overdrive) and guaranteed operation down to VCC = +1.1V support robust deployment in noisy, low-voltage systems.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free (indicated by "+T" suffix), 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 MAX6865UK31D3S+T, MAX6864UK31D3S+T provides identical supervision parameters but inverted reset polarity, while TPS3836K33DBVR trades off watchdog capability and nanopower operation for lower unit cost and broader distributor availability - making it suitable only for non-critical, non-battery-constrained applications.

Availability

MAX6865UK31D3S+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered IoT sensors, industrial handheld terminals, and low-power wearable electronics requiring stable component supply across extended production lifecycles.

Supply support for MAX6865UK31D3S+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 MAX68xx family delivers nanopower supervisory circuits optimized for battery longevity and reliability in portable and remote systems - specifically engineered to replace discrete reset solutions with integrated, factory-trimmed timing and watchdog functions.

FAQ

What is the exact reset threshold voltage of the MAX6865UK31D3S+T?

The MAX6865UK31D3S+T has a factory-trimmed reset threshold voltage of 3.075V, with ±2.5% tolerance over temperature (-40°C to +85°C). This value is defined by the "31" suffix in the part number and is confirmed in Table 2 (Threshold Suffix Guide) of the official Maxim datasheet. The threshold is guaranteed valid down to VCC = +1.1V, ensuring reliable brownout detection even during deep supply sag.

Does the MAX6865UK31D3S+T include a watchdog timer, and what is its timeout period?

Yes, the MAX6865UK31D3S+T includes a watchdog timer with a typical timeout period of 3.3s, indicated by the "S" suffix in the part number. The timer resets on any rising or falling edge at the WDI pin and expires only if WDI remains static longer than this period. It is disabled when RESET is asserted, and resumes counting immediately upon RESET deassertion - a behavior explicitly documented in the "Watchdog Input" section of the datasheet.

What type of reset output does the MAX6865UK31D3S+T provide, and how is it configured?

The MAX6865UK31D3S+T provides a push-pull active-high RESET output, as confirmed by its position in the Selector Guide (row MAX6865) and Pin Description table. Pin 1 drives high during reset assertion and low otherwise, referenced directly to VCC. No external pullup is required, and it meets VOH ≥ 0.8×VCC at 500µA source current - eliminating level-shifting components in 3.3V systems.

What is the minimum reset timeout period for the MAX6865UK31D3S+T, and how is it set?

The MAX6865UK31D3S+T has a fixed minimum reset timeout period of 150ms, specified by the "D3" suffix. This value is factory-programmed and cannot be altered externally. It guarantees RESET remains asserted for at least 150ms after VCC rises above 3.075V and MR is deasserted - sufficient for most 3.3V µPs to stabilize clocks and internal registers before release.

Is the MAX6865UK31D3S+T compatible with standard SOT23-5 footprints, and what packaging does it use?

Yes, the MAX6865UK31D3S+T uses a standard 5-pin SOT23-5 package with lead-free termination, as indicated by the "+T" suffix. Its pinout (RESET, GND, MR, WDI, VCC) matches the mechanical dimensions and land pattern of JEDEC MO-178AB, enabling drop-in replacement in existing SOT23-5 layouts. The device requires no modifications to PCB footprints or assembly processes.