Analog Devices Inc./Maxim Integrated MAX6865UK22D4S+T

Overview

The MAX6865UK22D4S+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, combining voltage monitoring (reset threshold = +2.235V), manual reset input (MR), and watchdog timer (WDI) with 209s typical timeout. It asserts an active-high push-pull RESET output during VCC brownout, MR assertion, or watchdog expiration, and guarantees valid reset down to VCC = +1.1V. It targets ultra-low-power portable medical and consumer devices requiring reliable power-on reset and software fault recovery.

For engineers reviewing the MAX6865UK22D4S+T datasheet, MAX6865UK22D4S+T pinout, MAX6865UK22D4S+T application, or MAX6865UK22D4S+T equivalent, this page delivers verified electrical parameters, confirmed SOT23-5 pin mapping, real-world timing behavior (tRP = 1200ms min, tWD = 209s typ), and validated alternative options for battery-powered system design.

Technical Context

This device integrates a precision bandgap-based voltage monitor with ±2.5% threshold accuracy over -40°C to +85°C, a glitch-immune 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 209s (typ). Its internal 10kΩ MR pullup eliminates external components.

The reset timeout period is factory-fixed at 1200ms (D4 option), and the active-high push-pull RESET output delivers VOH ≥ 0.8×VCC at ISOURCE = 500µA (VCC ≥ 2.38V) and VOL ≤ 0.3V at ISINK = 1.2mA (VCC ≥ 2.38V), ensuring robust interfacing with modern µP reset inputs.

Key Specifications

Pinout & Package

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

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6865UK22D4S+T, MAX6864UK22D4S+T offers identical supervision timing but inverted reset polarity, while TPS3837K22DBVR removes watchdog capability and increases quiescent current 15×-making it unsuitable for long-life or safety-critical embedded systems requiring autonomous error recovery.

Availability

MAX6865UK22D4S+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered IoT sensors, and low-power consumer electronics requiring stable component supply across extended production lifecycles.

Supply support for MAX6865UK22D4S+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 management, sensing, and interface applications in demanding industrial and medical environments.

The MAX68xx family delivers nanopower supervisory functions specifically for battery-constrained systems where runtime, reliability, and autonomous fault recovery are critical-enabling next-generation wearables and remote diagnostics.

FAQ

What is the exact reset threshold voltage of the MAX6865UK22D4S+T?

The MAX6865UK22D4S+T has a factory-trimmed reset threshold of +2.235V, with ±2.5% tolerance over -40°C to +85°C. This value is defined by the "22" suffix in the part number and is guaranteed in the Electrical Characteristics table. The MAX6865UK22D4S+T maintains this accuracy without external calibration or trimming components.

Does the MAX6865UK22D4S+T include a watchdog timer, and what is its timeout?

Yes, the MAX6865UK22D4S+T includes a watchdog timer with a typical timeout of 209 seconds (suffix "S"). It monitors the WDI input and triggers reset if no edge is detected within that period. The timer clears on any rising or falling edge at WDI, and is disabled while RESET is asserted. This behavior is fully documented in the MAX6865UK22D4S+T datasheet Section "WATCHDOG TIMER".

What type of RESET output does the MAX6865UK22D4S+T provide?

The MAX6865UK22D4S+T provides an active-high push-pull RESET output (Pin 1). It drives high (VOH ≥ 0.8×VCC) when reset is deasserted and low (VOL ≤ 0.3V) when asserted-requiring no external pullup resistor. This differs from open-drain or active-low variants in the MAX68xx family and is confirmed in the MAX6865UK22D4S+T Pin Description table.

What is the minimum supply voltage at which MAX6865UK22D4S+T guarantees valid RESET operation?

The MAX6865UK22D4S+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 characterized. This specification ensures deterministic reset state during deep brownout-critical for safe shutdown in MAX6865UK22D4S+T–based medical devices.

Is the MAX6865UK22D4S+T pin-compatible with other devices in the MAX68xx family?

Yes, the MAX6865UK22D4S+T uses the standard 5-pin SOT23-5 package and shares identical pinout with MAX6864/MAX6866/MAX6867/MAX6869 variants: Pin 1 = RESET, Pin 2 = GND, Pin 3 = MR, Pin 4 = WDI, Pin 5 = VCC. This mechanical and electrical compatibility allows drop-in substitution where function (e.g., RESET polarity, watchdog presence) matches system requirements.