Analog Devices Inc./Maxim Integrated MAX6865UK46D4L+T

Overview

The MAX6865UK46D4L+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 4.625V reset threshold (±2.5%), 1200ms minimum reset timeout, manual reset input (MR), and watchdog timer with 209s 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 MAX6865UK46D4L+T datasheet, MAX6865UK46D4L+T pinout, MAX6865UK46D4L+T application, or MAX6865UK46D4L+T equivalent, key selection criteria include its guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients (<40µs at 100mV overdrive), 200ns MR glitch rejection, and compatibility with noisy portable designs requiring low-quiescent-current supervision.

Technical Context

This device integrates voltage monitoring, a manual reset input (MR), and a watchdog timer (WDI) with independent timeout logic. The reset assertion is triggered by VCC falling below 4.625V, MR being pulled low, or WDI remaining static beyond 209s - all causing an active-high push-pull RESET output that remains asserted for ≥1200ms after recovery.

The internal architecture includes a precision bandgap reference, hysteresis-controlled comparator (0.5% VTH), noise-immune MR input with 10kΩ internal pullup, and edge-sensitive WDI detection capable of recognizing 150ns pulses. Reset deassertion timing is temperature-stable, with tRD < 40µs across –40°C to +85°C.

Key Specifications

Pinout & Package

MAX6865UK46D4L+T is housed in a lead-free 5-pin SOT23-5 package (2.9mm × 1.6mm × 1.1mm), optimized for space-constrained portable PCBs. Pin 1 is RESET (active-high push-pull), Pin 2 is GND, Pin 3 is MR (active-low manual reset), Pin 4 is WDI (watchdog input), and Pin 5 is VCC (supply monitor input).

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK46D4L+T, the MAX6865UK46D4L+T adds no functional redundancy but retains identical supervision specs while enabling future CT-based timeout flexibility; versus TPS3838K33DBVR, it delivers 10× lower ICC, 6× longer watchdog timeout, and precise 4.625V threshold - making it essential for modern ultra-low-power medical and portable electronics.

Availability

MAX6865UK46D4L+T is available at Aetrix Electronics and suitable for glucose monitors, patient vital sign recorders, industrial handheld scanners, and smart wearable trackers requiring stable component supply with guaranteed long-term manufacturability.

Supply support for MAX6865UK46D4L+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 was engineered specifically for ultra-low-power microprocessor supervision in battery-critical portable equipment, combining nanoscale BiCMOS process efficiency with robust reset timing and watchdog reliability.

FAQ

What is the exact reset threshold voltage of the MAX6865UK46D4L+T?

The MAX6865UK46D4L+T has a factory-trimmed reset threshold of +4.625V, with ±2.5% tolerance over the full –40°C to +85°C operating temperature range. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix '46' corresponds to 4.625V nominal. The MAX6865UK46D4L+T guarantees valid reset assertion down to VCC = +1.1V, ensuring reliability during deep brownout conditions.

Does the MAX6865UK46D4L+T support active-high or active-low reset output?

The MAX6865UK46D4L+T features an active-high push-pull RESET output (Pin 1), as confirmed in the MAX6865 pin description and Selector Guide. It drives high when asserting reset and returns low upon deassertion - eliminating need for external pullup resistors. This differs from open-drain or active-low variants in the same family, and the MAX6865UK46D4L+T's VOH is guaranteed ≥0.8×VCC under load.

What is the watchdog timeout period for the MAX6865UK46D4L+T?

The MAX6865UK46D4L+T uses the 'L' watchdog suffix, providing a typical timeout period of 209 seconds, with min/max values of 95s and 487s respectively. This long watchdog interval is designed for firmware with extended processing loops - such as sensor calibration or wireless handshake routines - and is cleared on any rising or falling edge at the WDI pin (Pin 4) of the MAX6865UK46D4L+T.

Can the MAX6865UK46D4L+T operate with supply voltages below 1.8V?

Yes, the MAX6865UK46D4L+T operates across VCC = 1.2V to 5.5V and guarantees RESET validity down to VCC = +1.1V, as specified in the Electrical Characteristics table. Its 170nA typical supply current at +25°C is measured at VCC = 1.8V, and performance remains stable across the full range - making the MAX6865UK46D4L+T suitable for single-cell Li-ion or alkaline-powered systems with deep discharge profiles.

Is the MAX6865UK46D4L+T pin-compatible with other devices in the MAX68xx family?

The MAX6865UK46D4L+T shares the same 5-pin SOT23-5 package and pinout (RESET, GND, MR, WDI, VCC) with MAX6864/MAX6866/MAX6867–MAX6869, but is not pin-compatible with MAX6861–MAX6863 (which use CT instead of WDI) or MAX6854–MAX6856 (which lack WDI). Its pin mapping matches the MAX6864UK46D4L+T exactly - enabling drop-in substitution where watchdog functionality is required.