Analog Devices Inc./Maxim Integrated MAX6865UK41D5L+T

Overview

The MAX6865UK41D5L+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 4.1V reset threshold (±2.5%), 300ms minimum reset timeout (D5), and integrated watchdog timer with 209s typical timeout (L suffix). It monitors VCC, responds to manual reset (MR), and asserts active-high push-pull RESET during brownout, power-up, or watchdog expiration - used in battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK41D5L+T datasheet, MAX6865UK41D5L+T pinout, MAX6865UK41D5L+T application, or MAX6865UK41D5L+T equivalent, key selection criteria include guaranteed RESET validity down to VCC = +1.1V, immunity to sub-40µs VCC transients, MR glitch rejection of 200ns, and compatibility with 1.2V–5.5V supply rails in space-constrained portable systems.

Technical Context

This device implements a precision bandgap-based voltage monitor with 0.5% reset threshold hysteresis (VHYST), a monostable reset timeout generator with ±25% tolerance over temperature, and an RC-free watchdog timer that clears on any WDI edge (rising or falling) and expires if WDI remains static beyond 209s (typ). The internal 10kΩ MR pullup enables direct switch interfacing without external components.

The MAX6865UK41D5L+T uses BiCMOS process technology (2848 transistors) to achieve nanoscale quiescent current while maintaining robust noise immunity: it rejects short VCC transients (e.g., ≤40µs at 100mV overdrive) and guarantees functional reset assertion even as VCC falls to +1.1V - critical for low-voltage battery operation in medical wearables.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5 (2.9mm × 1.6mm × 1.1mm), lead-free, RoHS-compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6865UK41D5L+T, the MAX6864UK41D5S+T offers faster watchdog response but sacrifices long-idle capability, while the TPS3838K33DBVR omits watchdog entirely and draws significantly more current - making MAX6865UK41D5L+T uniquely suited for 4.1V-rail medical wearables requiring decade-scale battery life and fail-safe supervision.

Availability

MAX6865UK41D5L+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign recorders, industrial handheld scanners, and smart wearable health trackers requiring stable component supply across extended production lifecycles.

Supply support for MAX6865UK41D5L+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 high-performance analog and mixed-signal ICs for precision sensing, power management, and reliable system supervision in demanding environments.

The MAX6865UK41D5L+T belongs to the MAX68xx nanopower supervisory family, engineered specifically for ultra-low-power medical, portable, and battery-critical applications where reset accuracy, watchdog reliability, and microamp-level current consumption are non-negotiable.

FAQ

What is the exact reset threshold voltage of the MAX6865UK41D5L+T?

The MAX6865UK41D5L+T has a factory-trimmed reset threshold of +4.100V with ±2.5% tolerance over temperature (−40°C to +85°C), corresponding to the "41" suffix in its part number per Maxim's Threshold Suffix Guide. This value is guaranteed across the full operating range and does not require external calibration.

Does the MAX6865UK41D5L+T require external components for basic operation?

No, the MAX6865UK41D5L+T operates autonomously with no external components required: it integrates a 10kΩ internal pullup on MR, precision voltage reference, and monostable timeout circuitry. Only a 0.1µF ceramic bypass capacitor on VCC to GND is recommended for noise suppression - no resistors, capacitors, or timing components are needed for reset or watchdog functions.

How does the watchdog timer in the MAX6865UK41D5L+T clear and expire?

The MAX6865UK41D5L+T watchdog timer clears on any rising or falling edge at the WDI pin (minimum pulse width 150ns) and expires only if WDI remains static (high or low) for longer than 209s (typical, L suffix). It does not count while RESET is asserted, and resumes timing immediately upon RESET deassertion - enabling robust firmware supervision without tight timing loops.

What is the minimum VCC voltage at which MAX6865UK41D5L+T guarantees valid RESET output?

The MAX6865UK41D5L+T guarantees valid RESET output down to VCC = +1.1V, meaning the active-high push-pull RESET signal remains logically defined and capable of driving a µP input even during severe brownout conditions - a critical feature for fail-safe operation in battery-powered medical devices.

Can the MAX6865UK41D5L+T be used with a 1.8V microcontroller supply rail?

Yes, the MAX6865UK41D5L+T operates from VCC = 1.2V to 5.5V and delivers a valid active-high push-pull RESET output compatible with 1.8V logic levels. Its VOH is guaranteed ≥0.8 × VCC at ISOURCE = 200µA, ensuring clean interface to 1.8V µPs without level-shifting circuitry - confirmed across −40°C to +85°C.