Analog Devices Inc./Maxim Integrated MAX6865UK30D2S+T

Overview

The MAX6865UK30D2S+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, factory-trimmed 3.000V reset threshold (±2.5%), and 40ms minimum reset timeout. It integrates manual reset input (MR), watchdog timer with 3.3s typical timeout, and push-pull active-high RESET output - designed for reliable power-on reset and brownout protection in battery-powered medical and portable electronics.

For engineers reviewing the MAX6865UK30D2S+T datasheet, MAX6865UK30D2S+T pinout, MAX6865UK30D2S+T application, or MAX6865UK30D2S+T equivalent, key selection criteria include its guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients (<40µs at 100mV overdrive), watchdog pulse detection as narrow as 150ns, and compatibility with CMOS-level MR/WDI inputs.

Technical Context

This device implements a dual-monitoring architecture: a precision voltage detector with hysteresis (0.5% of VTH) triggers reset on VCC drop below 3.000V, while an independent watchdog timer monitors WDI activity with 3.3s typical timeout (S-suffix). Reset assertion persists for ≥40ms after VCC recovery and MR deassertion, ensuring µP initialization completes before release.

The internal 10kΩ MR pullup enables direct connection to momentary switches without external components; the WDI input accepts pulses as short as 150ns and clears the watchdog on any edge transition. Push-pull active-high RESET delivers VOH ≥ 0.8×VCC at ISOURCE = 500µA (VCC ≥ 2.38V), supporting direct interfacing with µP reset inputs requiring high-true logic.

Key Specifications

Pinout & Package

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

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK30D2S+T and TPS3837K33DBVR, the MAX6865UK30D2S+T uniquely provides active-high RESET output with integrated watchdog - critical for systems where µP reset polarity and runtime fault detection are both mandatory design requirements.

Availability

MAX6865UK30D2S+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, MP3 players, and cell phones requiring stable component supply across extended production lifecycles.

Supply support for MAX6865UK30D2S+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 analog and mixed-signal ICs for power management, sensing, and interface applications.

The MAX68xx family was designed specifically for nanopower supervisory functions in battery-critical portable medical and consumer devices, emphasizing ultra-low ICC, precision voltage thresholds, and integrated watchdog reliability.

FAQ

What is the exact reset threshold voltage of the MAX6865UK30D2S+T?

The MAX6865UK30D2S+T has a factory-trimmed reset threshold voltage of 3.000V with ±2.5% tolerance over temperature (–40°C to +85°C), as defined by the "30" suffix in the part number per Table 2 of the datasheet. This value is guaranteed across the full operating range and includes hysteresis of 0.5% of VTH to prevent oscillation during slow VCC recovery.

Does the MAX6865UK30D2S+T require external components for basic operation?

No, the MAX6865UK30D2S+T requires no external components for core functionality: the MR input features an internal 10kΩ pullup to VCC, the voltage reference is trimmed on-die, and the RESET output is push-pull active-high. Only a 0.1µF ceramic capacitor from VCC to GND is recommended for noise suppression - no resistors, capacitors, or diodes are needed for reset generation or watchdog operation.

How does the watchdog timer in the MAX6865UK30D2S+T respond to WDI signal transitions?

The MAX6865UK30D2S+T watchdog timer clears on any rising or falling edge at the WDI pin and expires only if WDI remains static (high or low) for longer than the 3.3s typical timeout period. The timer does not count while RESET is asserted, and it resumes immediately upon RESET deassertion - enabling robust detection of firmware hangs without requiring precise pulse timing from the host µP.

What is the minimum VCC level at which the MAX6865UK30D2S+T guarantees valid RESET output?

The MAX6865UK30D2S+T guarantees valid RESET output down to VCC = +1.1V, meaning the active-high RESET signal remains logically correct (high when asserted, low when deasserted) even as the supply voltage collapses. Below +1.1V, RESET behavior is not specified, but the device continues to monitor VCC and will assert RESET again once VCC rises above the 3.000V threshold.

Can the MAX6865UK30D2S+T be used in systems with non-3.0V supply rails?

Yes, the MAX6865UK30D2S+T operates from VCC = 1.2V to 5.5V and monitors only its own VCC pin - it does not regulate or scale the supply. Its 3.000V reset threshold is fixed, so it is intended for systems where the monitored rail is nominally 3.0V (e.g., LiMnO₂ batteries, regulated 3.0V LDO outputs). For other rails, select a variant with matching threshold suffix (e.g., "23" for 2.3V, "45" for 4.5V).