Analog Devices Inc./Maxim Integrated MAX6865UK24D3S+T

Overview

The MAX6865UK24D3S+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, combining voltage monitoring (2.400V ±2.5% 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, maintaining reset for 150ms minimum after recovery - ideal for battery-powered glucose monitors and portable medical devices requiring long shelf life and reliable power-on initialization.

For engineers reviewing the MAX6865UK24D3S+T datasheet, MAX6865UK24D3S+T pinout, MAX6865UK24D3S+T application, or MAX6865UK24D3S+T equivalent, this page delivers verified functional identity, confirmed pin roles, exact reset timing behavior, watchdog immunity to software lockup, and validated alternative options for low-power µP supervision in space-constrained, single-supply systems.

Technical Context

The MAX6865UK24D3S+T implements a precision bandgap-based voltage monitor with guaranteed reset validity down to VCC = +1.1V and 0.5%VTH hysteresis to prevent chatter during slow VCC ramps. Its watchdog timer clears on any WDI edge (rising or falling) and expires only if WDI remains static beyond 209s (typ), making it suitable for infrequent but critical firmware health checks.

This device uses BiCMOS process technology (2848 transistors) and features internal 10kΩ MR pullup, 150ns WDI pulse width tolerance, and immunity to VCC transients ≤40µs at 100mV overdrive - enabling robust operation in noisy portable environments without external RC timing components.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount, 2.9mm × 1.6mm footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK24D3S+T and TPS3837K24DBVR, the MAX6865UK24D3S+T uniquely combines active-high RESET, 209s watchdog, and 170nA supply current - delivering optimal trade-off for battery-powered medical and portable electronics requiring both low power and autonomous fault recovery.

Availability

MAX6865UK24D3S+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, smart pagers, and industrial handheld terminals requiring stable component supply across extended production lifecycles.

Supply support for MAX6865UK24D3S+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 connectivity applications in industrial, medical, and consumer markets.

The MAX68xx family targets ultra-low-power microprocessor supervision in battery-critical systems, emphasizing nanopower operation, integrated watchdog, and factory-trimmed voltage thresholds for minimal design overhead.

FAQ

What is the exact reset threshold voltage of the MAX6865UK24D3S+T?

The MAX6865UK24D3S+T has a factory-trimmed reset threshold of 2.400V with ±2.5% tolerance over temperature (−40°C to +85°C). This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "24" corresponds to 2.400V nominal. The device guarantees valid reset assertion down to VCC = +1.1V, ensuring reliability during deep brownout conditions.

Does the MAX6865UK24D3S+T include a watchdog timer, and what is its timeout period?

Yes, the MAX6865UK24D3S+T includes a watchdog timer with a typical timeout period of 209s, designated 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 interval - providing robust detection of firmware hangs in low-duty-cycle portable devices.

What type of RESET output does the MAX6865UK24D3S+T provide, and how is it configured?

The MAX6865UK24D3S+T provides an active-high push-pull RESET output on Pin 1. Unlike open-drain variants, it requires no external pullup resistor and directly drives high during reset assertion. This configuration simplifies PCB layout and ensures fast, rail-to-rail reset signaling compatible with standard µP reset inputs expecting active-high logic.

What is the supply current consumption of the MAX6865UK24D3S+T under typical operating conditions?

The MAX6865UK24D3S+T draws only 170nA typical supply current at +25°C with VCC = 2.5V and no load - confirmed in the Electrical Characteristics table. This nanopower consumption enables multi-year operation on primary coin-cell batteries and makes the device especially suitable for always-on medical wearables and remote sensors.

How is the manual reset input (MR) implemented on the MAX6865UK24D3S+T?

The MR pin (Pin 3) on the MAX6865UK24D3S+T is an active-low input with an internal 10kΩ pullup to VCC. It accepts standard CMOS logic levels, requires no external components, and features 250ns MR-to-reset delay and 200ns glitch rejection. Driving MR low initiates reset for the full 150ms timeout period, even if MR returns high before expiration.