Analog Devices Inc./Maxim Integrated MAX6865UK19D6S+T

Overview

The MAX6865UK19D6S+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 1.9V reset threshold (suffix "19"), 1200ms minimum reset timeout (suffix "D6"), and watchdog timer with 3.3s typical timeout (suffix "S"). It monitors VCC, responds to manual reset (MR), and triggers reset on watchdog expiration - designed for battery-powered medical and portable electronics requiring guaranteed reset validity down to VCC = +1.1V.

For engineers reviewing the MAX6865UK19D6S+T datasheet, MAX6865UK19D6S+T pinout, MAX6865UK19D6S+T application, or MAX6865UK19D6S+T equivalent, key selection criteria include its active-high push-pull RESET output, watchdog input (WDI) timing compatibility, 1.9V threshold tolerance over temperature, and lead-free SOT23-5 footprint suitability for space-constrained PCB layouts.

Technical Context

This device integrates three core functions: precision voltage monitoring with ±2.5% threshold accuracy over -40°C to +85°C, a manual reset input with 1µs minimum pulse width and 250ns MR-to-reset delay, and a watchdog timer that clears on any WDI edge and expires after 3.3s (typ) if inactive - all operating from 1.2V to 5.5V supply.

The MAX6865UK19D6S+T uses internal BiCMOS process technology to achieve nanoscale quiescent current while maintaining robust noise immunity: it rejects VCC transients ≤40µs at 100mV overdrive and guarantees valid reset assertion down to VCC = +1.1V, enabling reliable operation during deep brownout conditions.

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 supervisory applications.

Compared with MAX6864UK19D6S+T and TPS3836K33DBVR, the MAX6865UK19D6S+T uniquely delivers active-high RESET, 170nA supply current, and integrated watchdog - making it the sole option for low-power, safety-critical portable designs requiring deterministic reset polarity and firmware supervision.

Availability

MAX6865UK19D6S+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, MP3 players, and smart pagers requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for MAX6865UK19D6S+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 portable applications.

The MAX68xx family was designed specifically for nanopower microprocessor supervision in battery-constrained systems - delivering precision voltage monitoring, manual reset, and watchdog functionality in minimal footprint with guaranteed operation down to 1.1V.

FAQ

What is the reset threshold voltage of the MAX6865UK19D6S+T?

The MAX6865UK19D6S+T has a factory-trimmed reset threshold of 1.9V with ±2.5% tolerance over -40°C to +85°C. This value is encoded in the "19" suffix per Maxim's Threshold Suffix Guide and is verified across temperature and supply voltage variations. The threshold remains stable with <0.5% normalized drift over temperature, ensuring consistent brownout detection in portable medical devices.

Does the MAX6865UK19D6S+T support active-high or active-low reset output?

The MAX6865UK19D6S+T features an active-high push-pull RESET output (pin 1), as confirmed by its position in the Selector Guide and Pin Description section for MAX6865. Unlike MAX6864 (active-low) or MAX6866 (open-drain), this variant drives high during reset assertion and requires no external pullup - directly compatible with µPs specifying active-high reset inputs.

What is the watchdog timeout period for the MAX6865UK19D6S+T?

The MAX6865UK19D6S+T implements a watchdog timer with a typical timeout period of 3.3 seconds, indicated by the "S" suffix in its part number. Electrical Characteristics confirm this is the "S" option (min 1.5s, typ 3.3s, max 7.75s). The timer clears on any rising or falling edge at WDI (pin 4) and expires only if WDI remains static beyond this interval.

Can the MAX6865UK19D6S+T operate below 1.2V supply voltage?

No - the absolute minimum recommended supply voltage for functional operation of the MAX6865UK19D6S+T is 1.2V, per the Electrical Characteristics table. However, its RESET output remains electrically valid down to VCC = +1.1V, meaning it will correctly assert reset even as supply collapses, though internal circuitry may not sustain full functionality below 1.2V.

Is the MAX6865UK19D6S+T pin-compatible with other MAX68xx supervisory ICs?

The MAX6865UK19D6S+T shares the same 5-pin SOT23-5 package and pinout (RESET, GND, MR, WDI, VCC) with MAX6864/MAX6866/MAX6867–MAX6869 variants. However, it is not pin-compatible with MAX6861–MAX6863 (which use CT pin) or MAX6854–MAX6856 (no WDI). Direct substitution requires matching RESET polarity and feature set.