Analog Devices Inc./Maxim Integrated MAX6865UK41D3L+T

Overview

The MAX6865UK41D3L+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 (MR), and watchdog timer (209s typical timeout) with ultra-low 170nA typical supply current. It asserts an active-high push-pull RESET output during VCC brownout, MR assertion, or watchdog timeout, and guarantees valid reset operation down to VCC = +1.1V - ideal for battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK41D3L+T datasheet, MAX6865UK41D3L+T pinout, MAX6865UK41D3L+T application, or MAX6865UK41D3L+T equivalent, key selection criteria include its factory-trimmed 4.100V threshold, 300ms minimum reset timeout (D3), L-suffix 209s watchdog period, active-high push-pull output, and SOT23-5 footprint compatibility with TPS3837.

Technical Context

This device integrates a precision voltage monitor with ±2.5% threshold accuracy over -40°C to +85°C, a glitch-immune manual reset input with 1µs minimum pulse width and 200ns noise rejection, and a watchdog timer that clears on any WDI edge and expires if WDI remains static beyond 209s (typ). The internal reset timeout generator ensures 300ms (min) assertion after VCC recovery or MR release.

The MAX6865UK41D3L+T uses BiCMOS process technology (2848 transistors) and features guaranteed RESET validity to VCC = +1.1V, immunity to VCC transients ≤40µs at 100mV overdrive, and no external components required - enabling direct integration into space-constrained, low-power embedded systems.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5 (lead-free, +T suffix), 2.9mm × 1.6mm footprint, 1.1mm height - compatible with standard pick-and-place and reflow processes.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6865UK41D3L+T, the S-suffix variant offers faster watchdog response but sacrifices long-interval coverage, while TPS3837K33DBVR provides pin-compatible simplicity at the cost of missing critical safety features like programmable timeout and watchdog - making MAX6865UK41D3L+T uniquely suited for certified medical and industrial fail-safe designs.

Availability

MAX6865UK41D3L+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign loggers, smart wearables, and low-power IoT sensor nodes requiring stable component supply across extended production lifecycles.

Supply support for MAX6865UK41D3L+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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, medical, and communications applications.

The MAX6854–MAX6869 family was designed specifically for ultra-low-power microprocessor supervision in battery-critical medical and portable electronics, integrating voltage monitoring, manual reset, and configurable watchdog functions in minimal footprint.

FAQ

What is the exact reset threshold voltage of the MAX6865UK41D3L+T?

The MAX6865UK41D3L+T has a factory-trimmed reset threshold of 4.100V, with ±2.5% tolerance over the full -40°C to +85°C operating temperature range. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix '41' corresponds to 4.100V nominal. The MAX6865UK41D3L+T maintains this accuracy without external calibration or trimming components.

Does the MAX6865UK41D3L+T support active-high or active-low reset output?

The MAX6865UK41D3L+T provides an active-high push-pull RESET output, as specified in its pin description (Pin 1 function) and Selector Guide. Unlike MAX6864/MAX6866 variants, the MAX6865UK41D3L+T drives RESET high during fault conditions (VCC drop, MR assertion, or watchdog timeout) and returns it low after the 300ms timeout. This matches µP reset inputs requiring active-high assertion.

What is the watchdog timeout period for the MAX6865UK41D3L+T, and how is it configured?

The MAX6865UK41D3L+T features an L-suffix watchdog timeout of 209s (typical), with min/max values of 95s and 487s respectively. This is fixed by the 'L' in the part number and requires no external configuration - the internal timer automatically expires if the WDI pin (Pin 4) remains static beyond this period. The MAX6865UK41D3L+T clears the timer on any WDI edge, supporting robust firmware health checking.

Can the MAX6865UK41D3L+T operate reliably at very low supply voltages?

Yes, the MAX6865UK41D3L+T guarantees valid RESET output down to VCC = +1.1V, as explicitly stated in the Electrical Characteristics table and Detailed Description section. Below this voltage, reset assertion remains functional but current-sinking capability degrades. For applications requiring RESET validity to 0V, a pulldown resistor on the push-pull RESET output is recommended - a design consideration unique to the MAX6865UK41D3L+T among its family.

Is the MAX6865UK41D3L+T pin-compatible with other supervisors in the same family?

The MAX6865UK41D3L+T uses the standard 5-pin SOT23-5 package and shares identical pinout (Pin 1: RESET, Pin 2: GND, Pin 3: MR, Pin 4: WDI, Pin 5: VCC) with MAX6864/MAX6866 variants. It is also pin-compatible with TPS3837 per the datasheet's feature list, enabling drop-in replacement in existing layouts - provided the active-high RESET behavior and L-suffix watchdog timing meet system requirements.