Analog Devices Inc./Maxim Integrated MAX6865UK44D6S+T

Overview

The MAX6865UK44D6S+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 4.266V (min) reset threshold, 1200ms minimum reset timeout, manual reset input (MR), and watchdog timer with 3.3s typical timeout. It monitors VCC in battery-powered systems to assert active-high push-pull RESET during brownout, power-up, or software fault conditions.

For engineers reviewing the MAX6865UK44D6S+T datasheet, MAX6865UK44D6S+T pinout, MAX6865UK44D6S+T application, or MAX6865UK44D6S+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 short as 150ns, and compatibility with CMOS-level MR/WDI inputs.

Technical Context

The MAX6865UK44D6S+T integrates voltage monitoring, a manual reset input, and a watchdog timer in a single BiCMOS IC. Its reset logic asserts active-high RESET when VCC falls below 4.266V (min), MR is pulled low, or WDI remains static beyond 3.3s (typ); reset remains asserted for ≥1200ms after recovery.

Watchdog functionality clears on any WDI edge (rising or falling), MR assertion, or RESET assertion - enabling robust software execution monitoring. The device operates across -40°C to +85°C with no external components required and guarantees valid reset output down to VCC = +1.1V.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount. Compact footprint (2.9mm × 1.6mm) suitable for space-constrained portable designs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK44D6S+T and TPS3836K33DBVR, the MAX6865UK44D6S+T uniquely delivers active-high push-pull RESET, 4.266V threshold precision, 1200ms timeout, and 3.3s watchdog in one nanopower package - making it optimal for 4.5V-system medical and portable electronics requiring both voltage and software fault coverage.

Availability

MAX6865UK44D6S+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, MP3 players, and cell phone baseband modules requiring stable component supply, long-term lifecycle support, and guaranteed lead-free compliance.

Supply support for MAX6865UK44D6S+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 high-performance analog and mixed-signal ICs for power, sensing, and interface applications in industrial, medical, and consumer markets.

The MAX6854–MAX6869 family targets ultra-low-power microprocessor supervision in battery-critical systems, combining voltage monitoring, manual reset, and watchdog functionality in minimal footprint and current budget.

FAQ

What is the exact reset threshold voltage range for MAX6865UK44D6S+T?

The MAX6865UK44D6S+T has a factory-trimmed reset threshold of 4.266V (min), 4.375V (typ), and 4.484V (max), corresponding to the "44" suffix per Maxim's Threshold Suffix Guide. This range is specified across -40°C to +85°C and ensures precise supervision of 4.5V rails with ±2.5% hysteresis.

Does MAX6865UK44D6S+T support active-high or active-low reset output?

The MAX6865UK44D6S+T provides an active-high push-pull RESET output (pin 1), as confirmed by its MAX6865 designation and pin description. It drives high when asserting reset and references to VCC - eliminating need for external pullup resistors unlike open-drain variants.

What watchdog timeout options are available for MAX6865UK44D6S+T?

The MAX6865UK44D6S+T uses the "S" suffix, specifying a watchdog timeout of 1.5s (min), 3.3s (typ), and 7.75s (max). This is distinct from the "L" suffix (95s–487s) and is optimized for mid-frequency firmware supervision in portable devices.

How does the manual reset (MR) input behave on MAX6865UK44D6S+T?

The MR input on MAX6865UK44D6S+T is active-low with internal 10kΩ pullup to VCC. Driving MR low asserts RESET for the full 1200ms timeout period, even if MR returns high earlier. Glitch rejection is 200ns, and minimum pulse width is 1µs - compatible with mechanical switches or digital logic.

Is MAX6865UK44D6S+T pin-compatible with other devices in the MAX68xx family?

Yes - MAX6865UK44D6S+T shares the same 5-pin SOT23-5 pinout as all MAX6864–MAX6869 variants. Pin 1 is RESET (active-high push-pull), pin 2 is GND, pin 3 is MR, pin 4 is WDI, and pin 5 is VCC. No PCB changes are needed when substituting within this watchdog-enabled subgroup.