Analog Devices Inc./Maxim Integrated MAX6865UK32D2S+T

Overview

The MAX6865UK32D2S+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 3.2V reset threshold (±2.5%), and a 40ms minimum reset timeout period. It integrates voltage monitoring, manual reset input (MR), and watchdog timer functionality with 3.3s typical watchdog timeout, and asserts an active-high push-pull RESET output. It is designed for reliable power-up/brownout supervision in battery-powered medical and portable electronics.

For engineers reviewing the MAX6865UK32D2S+T datasheet, MAX6865UK32D2S+T pinout, MAX6865UK32D2S+T application, or MAX6865UK32D2S+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 drive capability, and compatibility with 1.2V–5.5V supply rails.

Technical Context

The MAX6865UK32D2S+T implements a dual-monitoring architecture: a precision bandgap-based voltage detector triggers reset when VCC falls below 3.2V, while a separate watchdog timer monitors WDI activity with 3.3s typical timeout. Its internal 10kΩ MR pullup and glitch rejection (200ns) enable robust manual reset handling without external components.

This device uses BiCMOS process technology (2848 transistors) to achieve nanoscale quiescent current while maintaining guaranteed operation across –40°C to +85°C. The active-high push-pull RESET output is referenced to VCC and delivers VOH ≥ 0.8×VCC at ISOURCE = 500µA, supporting direct interface with µP reset inputs requiring high-true assertion.

Key Specifications

Pinout & Package

Package: 5-pin SOT23 (lead-free, +T suffix), footprint-compatible with industry-standard 5-lead SOT-23 packages and suitable for high-density PCB layouts.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK32D2S+T, the MAX6865UK32D2S+T provides native active-high reset drive, eliminating level-shifting overhead; versus TPS3836K33DBVR, it delivers 10× lower ICC and integrated watchdog-critical for long-life, safety-critical portable designs.

Availability

MAX6865UK32D2S+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered IoT sensors, industrial handheld terminals, and wearable health trackers requiring stable component supply and long-term lifecycle support.

Supply support for MAX6865UK32D2S+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) is a semiconductor company specializing in analog and mixed-signal ICs for power, sensing, and interface applications.

The MAX6854–MAX6869 family was designed specifically for nanopower microprocessor supervision in space-constrained, battery-operated systems where ultra-low ICC, precise voltage monitoring, and watchdog reliability are mandatory.

FAQ

What is the exact reset threshold voltage of the MAX6865UK32D2S+T?

The MAX6865UK32D2S+T has a factory-trimmed reset threshold of 3.200V with ±2.5% tolerance (3.12V to 3.28V) over –40°C to +85°C. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "32" corresponds to 3.200V nominal. The MAX6865UK32D2S+T maintains this accuracy without external calibration.

Does the MAX6865UK32D2S+T require external components for basic operation?

No, the MAX6865UK32D2S+T operates autonomously with no external components required. Its internal 10kΩ MR pullup resistor, precision voltage reference, and timing elements are fully integrated. Only a 0.1µF ceramic bypass capacitor from VCC to GND is recommended for noise immunity-no resistors, capacitors, or diodes are needed for reset generation or watchdog function.

How does the watchdog timer in the MAX6865UK32D2S+T respond to WDI signal edges?

The MAX6865UK32D2S+T watchdog timer clears on any rising or falling edge at the WDI pin-not just level transitions-ensuring robust detection of firmware activity. Edge sensitivity down to 150ns allows reliable clearing even with brief software-generated pulses. If WDI remains static longer than 3.3s (typical), the timer expires and triggers a full reset timeout period.

What is the minimum VCC voltage at which the MAX6865UK32D2S+T guarantees valid RESET output?

The MAX6865UK32D2S+T guarantees valid RESET output down to VCC = +1.1V, as specified in the Absolute Maximum Ratings and Electrical Characteristics tables. Below this voltage, RESET behavior is not guaranteed. This specification ensures deterministic reset assertion during deep brownout conditions common in battery-powered systems nearing end-of-life.

Is the MAX6865UK32D2S+T pin-compatible with other devices in the MAX68xx family?

The MAX6865UK32D2S+T shares the same 5-pin SOT23 package and pinout (RESET, GND, MR, WDI, VCC) with MAX6864, MAX6866, MAX6867, MAX6868, and MAX6869. However, it is not pin-compatible with MAX6861–MAX6863 (which use CT instead of WDI) or MAX6854–MAX6856 (which lack WDI). Always verify functional match-not just pin count-before substitution.