Analog Devices Inc./Maxim Integrated MAX6865UK24D1S+T

Overview

The MAX6865UK24D1S+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%), and a 10ms minimum reset timeout period. It integrates voltage monitoring, manual reset input (MR), and watchdog timer (WDI) with 3.3s typical timeout - designed for reliable power-up/brownout detection and code-execution error prevention in battery-critical systems.

For engineers reviewing the MAX6865UK24D1S+T datasheet, MAX6865UK24D1S+T pinout, MAX6865UK24D1S+T application, or MAX6865UK24D1S+T equivalent, this device delivers validated reset assertion down to VCC = +1.1V, immunity to sub-40µs VCC transients, and guaranteed push-pull active-high RESET output behavior across –40°C to +85°C.

Technical Context

The MAX6865UK24D1S+T implements a dual-trigger reset architecture: it asserts reset when VCC falls below 2.4V, when MR is pulled low, or when WDI remains static beyond its 3.3s watchdog timeout. Its internal timer ensures reset remains asserted for ≥10ms after VCC recovers and MR deasserts.

It features a CMOS-compatible MR input with 10kΩ internal pullup, a WDI input that clears the watchdog on any edge (min pulse width 150ns), and a push-pull active-high RESET output referenced to VCC with VOH ≥ 0.8×VCC at ISOURCE = 500µA and VOL ≤ 0.3V at ISINK = 1.2mA.

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 MAX6864UK24D1S+T and TPS3837K24DBVR, the MAX6865UK24D1S+T uniquely combines ultra-low ICC, active-high RESET, and integrated watchdog - making it optimal for space-constrained, battery-powered devices requiring autonomous fault recovery without µP-level software changes.

Availability

MAX6865UK24D1S+T is available at Aetrix Electronics and suitable for portable medical devices, industrial handheld scanners, smart meter data acquisition modules, and battery-backed IoT edge nodes requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX6865UK24D1S+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, mixed-signal, and power management ICs for industrial, medical, communications, and consumer applications - emphasizing reliability, low power, and integration.

The MAX6865UK24D1S+T belongs to Maxim's nanopower µP supervisory family, engineered specifically for battery-critical systems requiring guaranteed reset integrity, minimal quiescent current, and autonomous watchdog-based recovery - not general-purpose voltage monitoring.

FAQ

What is the exact reset threshold voltage of the MAX6865UK24D1S+T?

The MAX6865UK24D1S+T has a factory-trimmed reset threshold of 2.4V with ±2.5% tolerance over –40°C to +85°C. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "24" corresponds to VTH = 2.4V (typ). The MAX6865UK24D1S+T maintains this specification without external calibration or trimming components.

Does the MAX6865UK24D1S+T support active-high or active-low reset output?

The MAX6865UK24D1S+T provides a push-pull active-high RESET output - it drives high during reset assertion and low when deasserted. This is confirmed in the Pin Description section (page 8) and Selector Guide (page 16), where MAX6865 is explicitly marked under "Push-Pull ACTIVE HIGH". The MAX6865UK24D1S+T does not offer open-drain or active-low variants in this specific ordering.

What is the watchdog timeout period for the MAX6865UK24D1S+T?

The MAX6865UK24D1S+T features a watchdog timeout period of 3.3s (typical), with a minimum of 1.5s and maximum of 7.75s across temperature and process variation. This is defined by the "S" suffix in the part number and verified in Table 3 (Watchdog Timeout) of the datasheet. The timer resets on any WDI edge and triggers reset if WDI remains static beyond this interval.

Can the MAX6865UK24D1S+T operate reliably below 1.8V supply?

Yes - the MAX6865UK24D1S+T is fully specified from VCC = 1.2V to 5.5V and guarantees RESET validity down to VCC = +1.1V. Electrical Characteristics (page 2) confirm supply current (170nA typ), reset threshold (2.4V ±2.5%), and output drive capability remain functional at 1.2V. This makes the MAX6865UK24D1S+T suitable for single-cell Li-ion or alkaline systems with deep discharge profiles.

Is the MR input of the MAX6865UK24D1S+T internally pulled up?

Yes - the MR input of the MAX6865UK24D1S+T includes an internal 10kΩ pullup resistor to VCC, as documented in the Pin Description (page 8) and Applications Information (page 11). This allows MR to be left unconnected when unused, or driven directly by CMOS logic or open-drain outputs. The MAX6865UK24D1S+T requires no external pullup for basic manual reset functionality.