Analog Devices Inc./Maxim Integrated MAX6865UK38D4L+T

Overview

The MAX6865UK38D4L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, a factory-trimmed 3.800V reset threshold (±2.5%), and a 1200ms minimum reset timeout period. It integrates manual reset input (MR), watchdog timer with 209s typical timeout (L-suffix), and push-pull active-high RESET output - designed for reliable power-up/brownout monitoring in battery-critical systems like glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK38D4L+T datasheet, MAX6865UK38D4L+T pinout, MAX6865UK38D4L+T application, or MAX6865UK38D4L+T equivalent, key selection considerations include its guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients (<40µs at 100mV overdrive), watchdog pulse detection capability (150ns min), and lead-free SOT23-5 packaging compatibility with automated assembly.

Technical Context

This device belongs to Maxim's MAX6864–MAX6869 family of supervisory ICs with integrated watchdog functionality. Its internal architecture includes a precision voltage comparator for VCC monitoring, a digital watchdog timer cleared by WDI edge transitions, and an MR-synchronized reset timeout generator with fixed 1200ms delay (D4 option).

The MAX6865UK38D4L+T implements push-pull active-high RESET logic referenced to VCC, requires no external components, and guarantees valid reset assertion even as VCC falls to +1.1V - enabling robust operation in deep-battery-discharge scenarios common in single-cell Li-ion or alkaline-powered equipment.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, RoHS-compliant, footprint-compatible with industry-standard 5-pin SOT23 placements.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK38D4L+T and TPS3838K33DBVR, the MAX6865UK38D4L+T uniquely delivers active-high reset logic, 170nA power consumption, and integrated 209s watchdog - making it the sole fit for energy-constrained, active-high-reset µP systems requiring autonomous fault recovery.

Availability

MAX6865UK38D4L+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign loggers, and industrial handheld scanners requiring stable component supply across extended production lifecycles.

Supply support for MAX6865UK38D4L+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 MAX6864–MAX6869 product line targets ultra-low-power supervisory functions in battery-operated medical and portable electronics, emphasizing nanoscale current draw, wide VCC range, and integrated watchdog reliability.

FAQ

What is the exact reset threshold voltage of the MAX6865UK38D4L+T?

The MAX6865UK38D4L+T has a factory-trimmed reset threshold of 3.800V with ±2.5% tolerance over temperature (−40°C to +85°C), as defined by the '38' suffix per Maxim's Threshold Suffix Guide. This value is laser-trimmed during production and guaranteed in the Electrical Characteristics table under VTH parameter.

Does the MAX6865UK38D4L+T require external components for basic operation?

No, the MAX6865UK38D4L+T operates autonomously with no external components required. A 0.1µF ceramic capacitor from VCC to GND is recommended for noise immunity but not mandatory for functional reset assertion. No pullup/pulldown resistors, timing capacitors, or voltage dividers are needed.

How does the watchdog timer in the MAX6865UK38D4L+T respond to firmware activity?

The MAX6865UK38D4L+T watchdog timer clears on any rising or falling edge at the WDI pin - not on level states. It times out after 209s (typical) if no edge occurs, then asserts RESET for 1200ms. This edge-triggered behavior simplifies firmware integration, as the host µP only needs to toggle WDI periodically without precise pulse-width control.

Can the MAX6865UK38D4L+T operate reliably at very low supply voltages?

Yes, the MAX6865UK38D4L+T guarantees valid RESET assertion down to VCC = +1.1V, per the Absolute Maximum Ratings and Electrical Characteristics tables. Below this, reset behavior is not specified - but the 1.1V limit ensures robust operation during deep battery discharge in single-cell systems.

What is the function of Pin 1 (RESET) on the MAX6865UK38D4L+T?

Pin 1 of the MAX6865UK38D4L+T is the active-high push-pull RESET output. It drives high (to VCC) when VCC drops below 3.800V, MR is asserted low, or the watchdog times out. It remains high for the full 1200ms reset timeout period, then returns low - directly compatible with µPs requiring active-high reset inputs.