Analog Devices Inc./Maxim Integrated MAX6865UK33D5S+T

Overview

The MAX6865UK33D5S+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 3.3V reset threshold (±2.5%), 300ms minimum reset timeout, and integrated watchdog timer with 3.3s typical timeout. It monitors VCC, responds to manual reset (MR), and triggers reset on watchdog expiration - used in battery-powered medical and portable electronics for reliable power-on/power-fail sequencing.

For engineers reviewing the MAX6865UK33D5S+T datasheet, MAX6865UK33D5S+T pinout, MAX6865UK33D5S+T application, or MAX6865UK33D5S+T equivalent, key selection criteria include its 3.3V reset threshold accuracy, 300ms reset timeout (D5 option), 3.3s watchdog period (S suffix), active-low push-pull RESET output, and guaranteed reset validity down to VCC = +1.1V.

Technical Context

This device implements a precision voltage monitor with hysteresis (0.5% of VTH), a monostable reset timeout generator, and an edge-triggered watchdog timer that clears on any WDI transition. Its internal 10kΩ MR pullup and glitch rejection (200ns) enable robust manual reset handling without external components.

The watchdog operates independently of VCC monitoring: it expires only if WDI remains static beyond 3.3s (typ), and resets on rising/falling edges - supporting fail-safe software supervision in low-power embedded systems where CPU activity must be verified at runtime.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount, footprint compatible with industry-standard 5-lead SOT23.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK33D5S+T, the MAX6865UK33D5S+T offers identical supervision performance but is optimized for designs already routed for the MAX6865 pinout; versus TPS3836K33DBVR, it delivers 7× lower supply current and adds critical watchdog safety for autonomous embedded systems.

Availability

MAX6865UK33D5S+T is available at Aetrix Electronics and suitable for portable medical devices, industrial handheld terminals, and wireless sensor nodes requiring stable component supply across extended production lifecycles.

Supply support for MAX6865UK33D5S+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 demanding industrial, medical, and communications systems.

The MAX6854–MAX6869 family delivers nanopower supervisory functions - specifically engineered for battery-critical applications where sub-µA quiescent current, guaranteed brownout response, and integrated watchdog safety are mandatory.

FAQ

What is the exact reset threshold voltage of the MAX6865UK33D5S+T?

The MAX6865UK33D5S+T has a factory-trimmed reset threshold of 3.3V with ±2.5% tolerance over -40°C to +85°C. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "33" corresponds to VTH = 3.3V nominal. The device guarantees valid reset assertion down to VCC = +1.1V, ensuring reliability during deep brownout conditions.

Does the MAX6865UK33D5S+T include a watchdog timer, and what is its timeout period?

Yes, the MAX6865UK33D5S+T includes a watchdog timer with a typical timeout period of 3.3s, indicated by the "S" suffix in the part number. The timer clears on any rising or falling edge at the WDI pin and expires only if WDI remains static beyond this period. Minimum and maximum values are 1.5s and 7.75s respectively, per Table 3 in the datasheet.

What is the reset timeout duration for the MAX6865UK33D5S+T, and how is it selected?

The MAX6865UK33D5S+T has a fixed reset timeout of 300ms (minimum), denoted by the "D5" suffix. This value is one of six factory-programmed options ranging from 10ms to 1200ms. Unlike MAX6861–MAX6863 variants, the MAX6865UK33D5S+T does not feature a CT pin for dynamic timeout selection - the D5 option is permanently configured during manufacturing.

What type of reset output does the MAX6865UK33D5S+T provide, and what are its drive capabilities?

The MAX6865UK33D5S+T provides an active-low push-pull RESET output. It sources up to 200µA at VOH ≥ 0.8 × VCC and sinks up to 1.2mA at VOL ≤ 0.3V (for VCC ≥ 2.38V), enabling direct interface with standard CMOS microcontroller reset inputs without external pull-up resistors.

Is the MAX6865UK33D5S+T compatible with lead-free PCB assembly processes?

Yes, the "+T" suffix in MAX6865UK33D5S+T explicitly denotes lead-free packaging compliant with RoHS requirements. The device uses matte tin plating and is qualified for standard reflow profiles including JEDEC J-STD-020, supporting both Pb-free and mixed-technology assembly without solderability or reliability concerns.