Analog Devices Inc./Maxim Integrated MAX6865UK38D6S+T

Overview

The MAX6865UK38D6S+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 3.800V reset threshold (±2.5%), 1200ms minimum reset timeout, manual reset input (MR), and watchdog timer with 3.3s typical timeout. It asserts active-low push-pull RESET during VCC brownout, MR assertion, or watchdog expiration-used in battery-powered medical monitors and portable instrumentation.

For engineers reviewing the MAX6865UK38D6S+T datasheet, MAX6865UK38D6S+T pinout, MAX6865UK38D6S+T application, or MAX6865UK38D6S+T equivalent, key selection criteria include guaranteed RESET validity down to VCC = +1.1V, immunity to sub-40µs VCC transients, 10kΩ internal MR pullup, and compatibility with 1.2V–5.5V supply rails in space-constrained embedded systems.

Technical Context

This device integrates three core functions: precision voltage monitoring with hysteresis (0.5% of VTH), a glitch-immune manual reset input with 1µs minimum pulse width and 200ns noise rejection, and a watchdog timer that clears on any WDI edge and expires if WDI remains static beyond 3.3s (typ). The reset output remains asserted for ≥600ms after VCC recovery and MR release.

Its BiCMOS process enables stable operation across –40°C to +85°C with no external components required. The internal 10kΩ MR pullup eliminates external biasing, while the push-pull RESET output drives directly into µP reset inputs without pullup resistors-supporting logic-level compatibility across 1.2V–5.5V domains.

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 MAX6864UK38D6S+T and TPS3836K33DBVR, the MAX6865UK38D6S+T uniquely combines 3.8V precision threshold, 1200ms reset hold, integrated watchdog with 3.3s timeout, and nanopower operation-making it optimal for long-life, safety-critical portable instrumentation requiring both voltage and firmware supervision.

Availability

MAX6865UK38D6S+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign loggers, and industrial handheld scanners requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for MAX6865UK38D6S+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 interface applications in industrial, medical, and communications markets.

The MAX6854–MAX6869 family delivers nanopower supervisory functionality for battery-critical systems-specifically engineered to extend runtime while ensuring robust reset and watchdog behavior in portable medical and instrumentation equipment.

FAQ

What is the exact reset threshold voltage of the MAX6865UK38D6S+T?

The MAX6865UK38D6S+T has a factory-trimmed reset threshold of 3.800V with ±2.5% tolerance over temperature (–40°C to +85°C), corresponding to suffix "38" in the ordering code. This value is verified in the Threshold Suffix Guide (Table 2) and ensures accurate supervision of 3.3V system rails with sufficient margin against dropout. The MAX6865UK38D6S+T guarantees valid RESET assertion down to VCC = +1.1V, supporting deep brownout recovery.

Does the MAX6865UK38D6S+T include a watchdog timer, and what is its timeout?

Yes, the MAX6865UK38D6S+T includes a watchdog timer with a typical timeout of 3.3s (suffix "S"), with min/max values of 1.5s and 7.75s. The timer clears on any rising or falling edge at the WDI pin and expires only if WDI remains static beyond this period-ensuring detection of firmware hangs without false triggers. The MAX6865UK38D6S+T uses this feature to supervise µP execution in portable medical devices where runtime reliability is critical.

What is the reset timeout duration for the MAX6865UK38D6S+T, and how is it set?

The MAX6865UK38D6S+T has a fixed minimum reset timeout of 600ms (typical 900ms, maximum 1200ms), indicated by suffix "D6" in the part number. Unlike MAX6861–MAX6863 variants, it does not support pin-selectable timeout-the D6 option is factory-programmed and requires no external configuration. This ensures consistent reset hold time for µP initialization in battery-powered applications using the MAX6865UK38D6S+T.

What package type and pin count does the MAX6865UK38D6S+T use?

The MAX6865UK38D6S+T is housed in a 5-pin SOT23-5 package (2.9mm × 1.6mm), lead-free and RoHS-compliant. Its pinout is standardized across the MAX6864–MAX6869 series: Pin 1 = RESET (active-low push-pull), Pin 2 = GND, Pin 3 = MR, Pin 4 = WDI, Pin 5 = VCC. This compact footprint supports high-density PCB layouts in space-constrained portable devices using the MAX6865UK38D6S+T.

How does the MAX6865UK38D6S+T handle supply voltage transients?

The MAX6865UK38D6S+T is immune to short VCC transients up to 40µs in duration when the overdrive is 100mV-verified in the Typical Operating Characteristics graph (Figure MAX684 toc05). This prevents spurious resets caused by switching noise or load dumps in battery-powered systems. The MAX6865UK38D6S+T achieves this via internal filtering and hysteresis (0.5% of VTH), ensuring reliable operation in electrically noisy environments like industrial handheld scanners.