Analog Devices Inc./Maxim Integrated MAX6865UK41D5S+T

Overview

The MAX6865UK41D5S+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, combining voltage monitoring (4.100V reset threshold), manual reset input, and watchdog timer (3.3s typical timeout) with ultra-low 170nA typical supply current. It asserts an active-high push-pull RESET signal during VCC brownout, MR assertion, or watchdog timeout, and holds reset for 300ms minimum after recovery - ideal for battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK41D5S+T datasheet, MAX6865UK41D5S+T pinout, MAX6865UK41D5S+T application, or MAX6865UK41D5S+T equivalent, key selection criteria include its 4.100V factory-trimmed threshold, 300ms reset timeout, 3.3s watchdog period, guaranteed reset validity down to VCC = +1.1V, and compatibility with noisy low-voltage systems requiring minimal quiescent current.

Technical Context

This device implements a precision bandgap-based voltage monitor with ±2.5% threshold accuracy over temperature, coupled with a digital watchdog timer that clears on any WDI edge (rising or falling) and expires if WDI remains static beyond 3.3s (typ). The internal reset timeout generator is RC-based and factory-trimmed to 300ms (D5 option), with hysteresis of 0.5% VTH ensuring noise immunity against short VCC transients.

The MAX6865UK41D5S+T features an internally pulled-up MR input (10kΩ to VCC), active-high push-pull RESET referenced to VCC, and operates across 1.2V–5.5V supply range. Its BiCMOS process enables guaranteed reset assertion at VCC ≥ 1.1V while maintaining 170nA ICC (typ) at 2.5V/25°C - critical for multi-year battery life in wearable health electronics.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount, footprint compatible with JEDEC MO-178AB.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6865UK41D5S+T, the MAX6361KA29D3+T offers deeper undervoltage support but sacrifices watchdog protection and increases quiescent current 7×, while the TPS3808G33DBVR provides lower cost and identical footprint but omits both watchdog and programmable timeout - making neither a functional substitute without firmware or hardware redesign.

Availability

MAX6865UK41D5S+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered wearables, and low-power industrial sensors requiring stable component supply with long-term lifecycle assurance.

Supply support for MAX6865UK41D5S+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 demanding applications in industrial, medical, and communications markets.

The MAX68xx family delivers nanopower supervisory functions targeting battery-critical portable electronics - engineered to minimize ICC while guaranteeing robust reset timing and watchdog reliability across temperature and voltage extremes.

FAQ

What is the exact reset threshold voltage of the MAX6865UK41D5S+T?

The MAX6865UK41D5S+T has a factory-trimmed reset threshold of 4.100V, 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 "41" corresponds to 4.100V nominal. The device guarantees valid reset assertion down to VCC = +1.1V, independent of threshold accuracy.

Does the MAX6865UK41D5S+T include a watchdog timer, and what is its timeout period?

Yes, the MAX6865UK41D5S+T includes a watchdog timer with a typical timeout period of 3.3s, indicated by the "S" suffix in the part number. The timer clears on any rising or falling edge at the WDI pin and expires only if WDI remains static (high or low) beyond this period. Minimum and maximum values are 1.5s and 7.75s respectively, per Table 3.

What type of reset output does the MAX6865UK41D5S+T provide, and how is it configured?

The MAX6865UK41D5S+T provides an active-high push-pull RESET output (Pin 1), referenced to VCC. It drives high during reset conditions (VCC < 4.100V, MR low, or watchdog timeout) and low otherwise. Unlike open-drain variants, it requires no external pullup and can source/sink up to 1.2mA - directly compatible with µPs specifying active-high reset inputs.

What is the reset timeout period for the MAX6865UK41D5S+T, and how is it selected?

The MAX6865UK41D5S+T has a fixed reset timeout period of 300ms (minimum), denoted by the "D5" suffix. This value is factory-programmed and non-adjustable. It ensures sufficient hold time for µP clock stabilization and memory initialization after power recovery, and is validated across the full -40°C to +85°C temperature range.

How does the MAX6865UK41D5S+T handle supply voltage transients, and what is its immunity level?

The MAX6865UK41D5S+T is immune to short VCC transients up to 40µs duration when the overdrive is 100mV (i.e., VCC dips 100mV below 4.100V). This is specified in the "Maximum VCC Transient Duration vs. Reset Threshold Overdrive" graph (Figure MAX684 toc05). Its architecture filters noise without requiring external RC networks, reducing design complexity in EMI-prone environments.