Analog Devices Inc./Maxim Integrated MAX6865UK31D1L+T

Overview

MAX6865UK31D1L+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in 5-pin SOT23 package, featuring ultra-low 170nA typical supply current, factory-trimmed 3.075V reset threshold (suffix "31"), 10ms minimum reset timeout (suffix "D1"), and 209s typical watchdog timeout (suffix "L"). It monitors VCC, responds to manual reset (MR), and triggers reset on watchdog timeout - designed for battery-critical applications like glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK31D1L+T datasheet, MAX6865UK31D1L+T pinout, MAX6865UK31D1L+T application, or MAX6865UK31D1L+T equivalent, this page delivers verified functional identity, exact reset threshold and timeout values, watchdog timing behavior, MR/WDI interface logic levels, and validated alternative options for low-power µP supervision.

Technical Context

The MAX6865UK31D1L+T integrates voltage monitoring, manual reset input (MR), and watchdog timer (WDI) in a single BiCMOS IC. Its reset assertion is triggered by VCC falling below 3.075V ±2.5%, MR low pulse ≥1µs, or WDI inactivity exceeding 209s (typ). Reset remains asserted for ≥10ms after VCC recovery and MR deassertion.

It uses internal 10kΩ MR pullup and supports CMOS-level WDI transitions with 150ns minimum pulse width detection. The watchdog timer clears on any WDI edge, MR assertion, or RESET assertion - ensuring robust software execution monitoring without false timeouts.

Key Specifications

Pinout & Package

MAX6865UK31D1L+T is housed in a lead-free 5-pin SOT23-5 package (JEDEC MO-178AA), footprint-compatible with industry-standard 5-pin SOT23 layouts. Pin 1 is marked with a dot; device orientation follows standard SOT23 top-view convention.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6865UK31D1L+T, MAX6864UK31D1L+T offers identical supervision timing but requires external biasing for RESET, while TPS3836K33DBVR trades ultra-low power and watchdog capability for simpler fixed-threshold operation - making MAX6865UK31D1L+T optimal for battery-constrained, safety-critical embedded systems requiring both precision reset and long-interval watchdog coverage.

Availability

MAX6865UK31D1L+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, and smart hearing aids requiring stable component supply with guaranteed long-term availability and full traceability.

Supply support for MAX6865UK31D1L+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 in demanding industrial, medical, and automotive applications.

The MAX6854–MAX6869 family was engineered specifically for ultra-low-power microprocessor supervision in battery-operated medical and portable electronics, emphasizing nanoscale current consumption, guaranteed sub-1.2V reset validity, and robust watchdog reliability.

FAQ

What is the exact reset threshold voltage of MAX6865UK31D1L+T?

The MAX6865UK31D1L+T has a factory-trimmed reset threshold of 3.075V, with ±2.5% tolerance over temperature (–40°C to +85°C). This value is confirmed by the "31" suffix in the part number per Maxim's Threshold Suffix Guide (Table 2), and is optimized for reliable supervision of 3.3V systems experiencing brownout conditions.

Does MAX6865UK31D1L+T include a watchdog timer, and what is its timeout?

Yes, MAX6865UK31D1L+T includes a watchdog timer with a typical timeout of 209s, indicated by the "L" suffix. The timer resets on any rising or falling edge at the WDI pin and triggers a reset if no transition occurs within that period - providing long-cycle firmware supervision ideal for medical devices with infrequent processing tasks.

What type of reset output does MAX6865UK31D1L+T provide?

MAX6865UK31D1L+T provides an active-low push-pull RESET output (Pin 1). It actively drives low during reset and actively pulls high when deasserted - eliminating the need for an external pullup resistor and enabling direct connection to standard CMOS µP reset inputs.

How does the manual reset (MR) input function on MAX6865UK31D1L+T?

The MR input on MAX6865UK31D1L+T is active-low with internal 10kΩ pullup to VCC. A logic-low pulse ≥1µs asserts reset, which remains active for the full 10ms timeout after MR returns high. No external components are required - a simple momentary switch from MR to GND implements field-serviceable reset capability.

Is MAX6865UK31D1L+T compatible with 1.8V or 2.5V supply rails?

Yes, MAX6865UK31D1L+T operates across 1.2V to 5.5V VCC and guarantees reset assertion down to VCC = 1.1V. Its 3.075V threshold is appropriate for 3.3V systems, but the device itself functions correctly with 1.8V or 2.5V supplies - enabling use in multi-rail systems where it supervises only the 3.3V domain while powered from a lower auxiliary rail.