Analog Devices Inc./Maxim Integrated MAX6865UK46D4S+T

Overview

The MAX6865UK46D4S+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 4.625V reset threshold (±2.5%), 1200ms minimum reset timeout, manual reset input (MR), and watchdog timer with 3.3s typical timeout. It asserts an active-high push-pull RESET during VCC brownout, MR assertion, or watchdog expiration-used in battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6865UK46D4S+T datasheet, MAX6865UK46D4S+T pinout, MAX6865UK46D4S+T application, or MAX6865UK46D4S+T equivalent, key selection criteria include its guaranteed reset validity down to VCC = +1.1V, immunity to short VCC transients (<40µs at 100mV overdrive), push-pull active-high output logic, and lead-free SOT23-5 packaging for space-constrained embedded systems.

Technical Context

This device integrates voltage monitoring, a manual reset input with 250ns MR-to-reset delay and 1µs minimum pulse width, and a watchdog timer that clears on any WDI edge and expires if WDI remains static beyond 3.3s (typ). Its BiCMOS process ensures stable operation across -40°C to +85°C with no external components required.

The internal reset timeout generator guarantees ≥1200ms assertion after VCC recovery or MR release, while the 10kΩ internal MR pullup eliminates external biasing. The push-pull active-high RESET output delivers VOH ≥ 0.8×VCC at ISOURCE = 500µA (VCC ≥ 2.38V) and VOL ≤ 0.3V at ISINK = 1.2mA (VCC ≥ 2.38V), enabling direct interfacing with 1.8V–5.5V µP reset inputs.

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 MAX6864UK46D4S+T, the MAX6865UK46D4S+T offers identical core supervision but is not pin-compatible due to different RESET polarity (active-high vs. active-low in MAX6864); versus TPS3838K33DBVR, it delivers 10× lower ICC, adjustable threshold, integrated watchdog, and push-pull drive-enabling next-gen ultra-low-power medical wearables.

Availability

MAX6865UK46D4S+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered instrumentation, and industrial handheld scanners requiring stable component supply with long-term lifecycle support.

Supply support for MAX6865UK46D4S+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 communications markets.

The MAX6854–MAX6869 family delivers nanopower supervisory functions with integrated watchdog and manual reset for battery-critical embedded systems-targeting multi-year operation in portable health and IoT endpoints.

FAQ

What is the exact reset threshold voltage of the MAX6865UK46D4S+T?

The MAX6865UK46D4S+T has a factory-trimmed reset threshold of 4.625V (typical), with ±2.5% tolerance over temperature and supply voltage. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "46" corresponds to VTH = 4.625V. The device guarantees valid reset assertion down to VCC = +1.1V, making it suitable for brownout detection in Li-ion and multi-cell alkaline systems.

Does the MAX6865UK46D4S+T support active-high or active-low reset output?

The MAX6865UK46D4S+T features an active-high push-pull RESET output, as confirmed in the MAX6865 pin description (page 8) and Selector Guide (page 16). Pin 1 delivers RESET high during fault conditions (VCC < 4.625V, MR low, or WDI timeout) and returns low after the 1200ms timeout expires. This eliminates need for external inverters or pullup resistors in systems requiring active-high reset signaling.

What is the watchdog timeout period for the MAX6865UK46D4S+T?

The MAX6865UK46D4S+T implements a watchdog timeout period of 3.3s (typical), specified by the "S" suffix in its part number. Per Table 3 (Watchdog Timeout), the S-suffix yields min/typ/max values of 1.5s/3.3s/7.75s. The watchdog clears on any rising or falling edge at WDI (pin 4) and expires only if WDI remains static beyond this window-critical for detecting firmware hangs in intermittent-sensing applications.

Is the MAX6865UK46D4S+T pin-compatible with other devices in the MAX68xx family?

The MAX6865UK46D4S+T uses the standard 5-pin SOT23-5 package and shares identical pinout with MAX6864/MAX6866 variants (pin 1 = RESET, pin 2 = GND, pin 3 = MR, pin 4 = WDI, pin 5 = VCC). However, it is not pin-compatible with MAX6861–MAX6863 (which use CT instead of WDI) or MAX6854–MAX6856 (which lack WDI). Always verify RESET polarity and WDI presence before substitution.

What is the supply current specification for the MAX6865UK46D4S+T under operating conditions?

The MAX6865UK46D4S+T draws 170nA typical supply current (ICC) at VCC = 1.8V, TA = +25°C, with reset deasserted-per Electrical Characteristics table (page 2). At VCC = 3.3V, ICC is 190nA (typ); at VCC = 5.0V, it rises to 210nA (typ). This ultra-low ICC enables >10-year battery life in coin-cell–powered devices when paired with low-duty-cycle µPs.