Analog Devices Inc./Maxim Integrated MAX6865UK42D2L+T

Overview

The MAX6865UK42D2L+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 4.200V reset threshold (±2.5%), and dual watchdog timeout options (3.3s or 209s typ). It integrates voltage monitoring, manual reset input (MR), and watchdog timer (WDI) to prevent code-execution errors in battery-powered medical and portable electronics.

For engineers reviewing the MAX6865UK42D2L+T datasheet, MAX6865UK42D2L+T pinout, MAX6865UK42D2L+T application, or MAX6865UK42D2L+T equivalent, this device is selected for low-power brownout protection, system-level fault recovery, and watchdog supervision where VCC operation down to +1.1V and immunity to short VCC transients are required.

Technical Context

The MAX6865UK42D2L+T implements a precision bandgap-based voltage monitor with 2.5% threshold tolerance over -40°C to +85°C, coupled with a digital watchdog timer that clears on any WDI edge and expires if WDI remains static beyond the selected timeout (L = 209s typ). Its internal 10kΩ MR pullup and glitch rejection (200ns) enable robust manual reset without external components.

Reset assertion is guaranteed valid down to VCC = +1.1V, and the push-pull active-high RESET output drives high with VOH ≥ 0.8×VCC at ISOURCE = 500µA (VCC ≥ 2.38V). The device uses BiCMOS process technology and contains 2848 transistors, optimized for minimal quiescent current across its full operating range.

Key Specifications

Pinout & Package

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

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK42D2L+T and TPS3838K33DBVR, the MAX6865UK42D2L+T uniquely delivers active-high RESET, ultra-low 170nA ICC, and integrated 209s watchdog - making it optimal for space-constrained, battery-critical medical and portable systems requiring both precise threshold control and long-loop fault detection.

Availability

MAX6865UK42D2L+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, MP3 players, and legacy cell phone modules requiring stable component supply with guaranteed long-term availability and traceable sourcing.

Supply support for MAX6865UK42D2L+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 management, sensing, and interface applications in industrial, medical, and consumer markets.

The MAX6854–MAX6869 family was engineered specifically for nanopower microprocessor supervision in battery-operated medical and portable equipment, emphasizing ultra-low ICC, wide VCC operating range, and integrated watchdog reliability.

FAQ

What is the reset threshold voltage of the MAX6865UK42D2L+T?

The MAX6865UK42D2L+T has a factory-trimmed reset threshold of 4.200V with ±2.5% tolerance over temperature (-40°C to +85°C), corresponding to the "42" suffix in the part number per Maxim's Threshold Suffix Guide. This value is guaranteed by design and tested across the full operating range, ensuring accurate brownout detection for 3.3V and 5V systems.

Does the MAX6865UK42D2L+T include a watchdog timer, and what are its timeout options?

Yes, the MAX6865UK42D2L+T includes a watchdog timer with two selectable timeout periods: "S" (3.3s typ) and "L" (209s typ), indicated by the final letter in the part number. The "L" suffix in MAX6865UK42D2L+T confirms the 209s typical timeout, which is ideal for long-duration firmware loops in medical devices where infrequent but critical supervision is required.

What type of reset output does the MAX6865UK42D2L+T provide?

The MAX6865UK42D2L+T provides an active-high push-pull RESET output (pin 1), meaning it drives high during reset assertion and low when deasserted. This is confirmed by its position in the Selector Guide and Pin Description section for MAX6865, distinguishing it from open-drain or active-low variants in the same family.

What is the minimum supply voltage at which the MAX6865UK42D2L+T guarantees valid reset operation?

The MAX6865UK42D2L+T guarantees valid reset assertion down to VCC = +1.1V, as specified in the Electrical Characteristics table. This ensures reliable brownout detection even during deep discharge of single-cell lithium or alkaline batteries, a critical requirement for portable medical devices where system failure must be avoided at all VCC levels.

How does the manual reset (MR) input function on the MAX6865UK42D2L+T?

The MR input on the MAX6865UK42D2L+T is active-low with an internal 10kΩ pullup to VCC. Driving MR low initiates a reset that persists for the full 40ms timeout period (D2 option) after MR returns high. It accepts standard CMOS logic levels and requires no external components, supporting direct connection to momentary switches or FPGA I/O pins without debounce circuitry.