Analog Devices Inc./Maxim Integrated MAX6865UK24D3L+T

Overview

The MAX6865UK24D3L+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 2.4V reset threshold (±2.5%), 225ms minimum reset timeout (D3), and integrated watchdog timer with 209s typical timeout (L suffix). It monitors VCC, responds to manual reset (MR), and triggers reset on watchdog expiration - used in battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK24D3L+T datasheet, MAX6865UK24D3L+T pinout, MAX6865UK24D3L+T application, or MAX6865UK24D3L+T equivalent, key selection criteria include its guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients (<40µs at 100mV overdrive), push-pull active-high RESET output, and compatibility with noisy low-power systems requiring long watchdog intervals.

Technical Context

This device implements a dual-monitoring architecture: a precision voltage detector with hysteresis (0.5% of VTH) ensures stable reset assertion/deassertion during brownout recovery, while an independent watchdog timer clears on any WDI edge and expires only after sustained inactivity (>209s typ). The internal 10kΩ MR pullup and glitch rejection (200ns) support direct switch interfacing without external components.

The push-pull active-high RESET output is referenced to VCC and delivers VOH ≥ 0.8×VCC (at ISOURCE = 500µA) and VOL ≤ 0.3V (at ISINK = 1.2mA), enabling direct connection to µP reset inputs across 1.2V–5.5V supply ranges. No external capacitor or resistor is required for basic operation.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount, footprint compatible with industry-standard 5-pin SOT23 layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK24D3S+T and TPS3836K24DBVR, the MAX6865UK24D3L+T uniquely combines ultra-low ICC, precise 2.4V monitoring, 225ms reset hold, and long-interval (209s) watchdog - making it optimal for infrequently active, battery-constrained medical and industrial sensors where both power and reliability are critical.

Availability

MAX6865UK24D3L+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered IoT sensors, and industrial handheld equipment requiring stable component supply across extended temperature ranges (-40°C to +85°C) and long product lifecycles.

Supply support for MAX6865UK24D3L+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 demanding industrial, medical, and automotive environments.

The MAX6865UK24D3L+T belongs to the MAX68xx nanopower supervisory family, engineered specifically for ultra-low-power, high-reliability monitoring in battery-operated medical and portable electronics where reset accuracy and watchdog robustness are non-negotiable.

FAQ

What is the exact reset threshold voltage of the MAX6865UK24D3L+T?

The MAX6865UK24D3L+T has a factory-trimmed reset threshold of 2.4V with ±2.5% tolerance over the full -40°C to +85°C temperature range. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "24" corresponds to VTH = 2.4V nominal. The MAX6865UK24D3L+T guarantees reset assertion when VCC falls below this threshold and deassertion only after VCC exceeds it plus hysteresis (0.5% of VTH).

Does the MAX6865UK24D3L+T support active-high or active-low reset outputs?

The MAX6865UK24D3L+T features an active-high push-pull RESET output (Pin 1), as confirmed by its pin description and Selector Guide entry. Unlike open-drain or active-low variants, this output drives high (≥0.8×VCC) when deasserted and low (≤0.3V) when asserted - eliminating the need for an external pullup resistor and simplifying interface to µPs with active-high reset inputs.

What is the watchdog timeout period for the MAX6865UK24D3L+T?

The MAX6865UK24D3L+T has a watchdog timeout period of 209s typical (L suffix), with min/max values of 95s/487s over temperature. This long interval is designed for applications with infrequent firmware activity, such as hourly sensor sampling. The watchdog timer clears on any rising or falling edge at WDI (Pin 4) and expires only if WDI remains static beyond this period.

Can the MAX6865UK24D3L+T operate reliably at VCC = 1.2V?

Yes - the MAX6865UK24D3L+T is fully specified from VCC = 1.2V to 5.5V, and its reset output remains valid down to VCC = +1.1V. At 1.2V, supply current is 190nA typical, reset threshold is maintained at 2.4V ±2.5%, and RESET output meets VOL ≤ 0.3V (ISINK = 100µA) and VOH ≥ 0.8×VCC (ISOURCE = 200µA), ensuring interoperability with low-voltage µPs.

Is the MAX6865UK24D3L+T pin-compatible with other MAX68xx devices?

The MAX6865UK24D3L+T uses the standard 5-pin SOT23-5 package and shares identical pinout (VCC, WDI, MR, GND, RESET) with MAX6864/MAX6866/MAX6867–MAX6869. However, it is not pin-compatible with MAX6854–MAX6863 (which lack WDI) or MAX6858/MAX6860 (which lack MR). Always verify function alignment - e.g., MAX6865UK24D3L+T's active-high RESET differs from MAX6864's active-low variant.