Analog Devices Inc./Maxim Integrated MAX6865UK38D2L+T

Overview

The MAX6865UK38D2L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, combining voltage monitoring, manual reset input (MR), and watchdog timer (WDI) functions. It asserts an active-high push-pull RESET output when VCC drops below 3.705V (typ), MR is pulled low, or the watchdog expires after 209s (typ). Designed for ultra-low-power systems, it draws only 170nA (typ) supply current and guarantees valid reset operation down to VCC = +1.1V.

For engineers reviewing the MAX6865UK38D2L+T datasheet, MAX6865UK38D2L+T pinout, MAX6865UK38D2L+T application, or MAX6865UK38D2L+T equivalent, this device serves as a critical power-on reset and fault recovery component in battery-constrained embedded systems where supply stability, software execution integrity, and long-term energy efficiency are essential.

Technical Context

The MAX6865UK38D2L+T implements a precision bandgap-based voltage monitor with ±2.5% threshold accuracy over temperature, paired with a digitally timed watchdog that clears on any WDI edge and times out after 209s (typ) if inactive. Its internal 10kΩ MR pullup enables direct switch interfacing without external components.

This variant features an active-high push-pull RESET output referenced to VCC, a fixed 40ms minimum reset timeout (D2 option), and factory-trimmed 3.705V (typ) reset threshold - confirmed by suffix "38" per Threshold Suffix Guide (Table 2) and "D2" per Reset Timeout Period Table (Table 4).

Key Specifications

Pinout & Package

MAX6865UK38D2L+T is housed in a lead-free 5-pin SOT23-5 package (JEDEC MO-178AA), with 1.3mm × 2.9mm footprint and 0.95mm height. Pin 1 is marked with a dot; pin numbering follows standard SOT23 orientation (counterclockwise from mark).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK38D2S+T and TPS3837K33DBVR, the MAX6865UK38D2L+T uniquely delivers 209s watchdog supervision alongside precise 3.705V threshold and 40ms reset hold - making it the sole fit for battery-powered systems requiring both long-interval firmware validation and tight brownout detection.

Availability

MAX6865UK38D2L+T is available at Aetrix Electronics and suitable for portable medical devices, industrial handheld terminals, wearable health monitors, and smart meter data loggers requiring stable component supply across extended product lifecycles.

Supply support for MAX6865UK38D2L+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 management, sensing, and interface applications in industrial, medical, and communications markets.

The MAX6865UK38D2L+T belongs to the MAX6854–MAX6869 nanopower supervisory family, engineered specifically for ultra-low-current battery-operated systems needing integrated voltage monitoring, manual reset, and configurable watchdog supervision.

FAQ

What is the exact reset threshold voltage of the MAX6865UK38D2L+T?

The MAX6865UK38D2L+T has a factory-trimmed reset threshold voltage of 3.705V (typical), with ±2.5% tolerance over -40°C to +85°C. This value is confirmed by the "38" suffix in the part number per Maxim's Threshold Suffix Guide (Table 2), and applies to VCC falling conditions. The device guarantees valid reset assertion down to VCC = +1.1V, supporting robust operation during deep brownout events.

Does the MAX6865UK38D2L+T include a watchdog timer, and what is its timeout period?

Yes, the MAX6865UK38D2L+T includes a watchdog timer with a typical timeout period of 209 seconds, indicated by the "L" 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 beyond this period. It remains disabled during reset assertion and resumes counting immediately upon reset deassertion - a behavior verified in the Functional Diagram and Watchdog Timing section of the datasheet.

What type of reset output does the MAX6865UK38D2L+T provide, and how is it configured?

The MAX6865UK38D2L+T provides an active-high push-pull RESET output, as confirmed by its position in the Selector Guide (row MAX6865) and Pin Description table. This output drives high during reset assertion and low when deasserted, referenced to VCC, eliminating the need for an external pullup resistor. It sources up to 500µA at VOH ≥ 0.8×VCC and sinks up to 1.2mA at VOL ≤ 0.3V - specifications validated across 1.71V–2.38V VCC range.

What is the minimum reset timeout period for the MAX6865UK38D2L+T, and how is it selected?

The MAX6865UK38D2L+T has a fixed minimum reset timeout period of 40ms, specified by the "D2" suffix per Table 4 (Reset Timeout Periods). Unlike variants with CT pin (e.g., MAX6861–MAX6863), this device does not support pin-selectable timeout - the 40ms/60ms/80ms option is permanently configured at wafer sort. This ensures deterministic timing behavior without external dependencies or configuration errors.

Is the MAX6865UK38D2L+T compatible with 1.8V or 2.5V supply rails?

Yes, the MAX6865UK38D2L+T operates across a supply range of 1.2V to 5.5V and is fully functional at 1.8V and 2.5V. Its 170nA typical supply current and guaranteed reset validity down to VCC = +1.1V make it suitable for low-voltage microcontrollers. Electrical characteristics - including VOH, VOL, and ICC - are explicitly characterized at 1.8V and 2.5V in the Electrical Characteristics tables, confirming interoperability with modern ultra-low-power SoCs.