Analog Devices Inc./Maxim Integrated MAX6865UK17D4S+T

Overview

The MAX6865UK17D4S+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, combining voltage monitoring, manual reset input (MR), and watchdog timer (WDI) functions. It asserts an active-low push-pull RESET when VCC drops below 1.665V (±2.5%), MR is pulled low, or the watchdog times out after 3.3s (typ). Designed for ultra-low-power systems, it draws only 170nA (typ) at 2.5V and guarantees valid reset down to VCC = 1.1V.

For engineers reviewing the MAX6865UK17D4S+T datasheet, MAX6865UK17D4S+T pinout, MAX6865UK17D4S+T application, or MAX6865UK17D4S+T equivalent, this device is selected for battery-powered medical monitors, portable instrumentation, and embedded systems requiring guaranteed brownout immunity, glitch-resistant reset timing, and watchdog supervision without external components.

Technical Context

The MAX6865UK17D4S+T implements a precision bandgap-based voltage monitor with 2.5% threshold tolerance and 0.5% hysteresis, paired with a temperature-stable RC-based watchdog timer. Its internal 10kΩ MR pullup enables direct switch interfacing, while the WDI input detects edges ≥150ns and clears the watchdog on any transition.

Reset assertion is synchronized to VCC crossing the 1.665V threshold, followed by a fixed 1200ms timeout (D4 option) before deassertion. The push-pull RESET output drives high to VCC − 0.3V (ISINK = 1.2mA) and low to ≤0.3V (ISOURCE = 500µA), ensuring robust logic-level compatibility across 1.2V–5.5V supply ranges.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount. Compact 2.9mm × 1.6mm footprint with 0.95mm height, optimized for space-constrained portable designs.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK16D3S+T and TPS3836K33DBVR, the MAX6865UK17D4S+T uniquely combines 1.665V threshold, 1200ms timeout, and 3.3s watchdog in a 170nA package-making it optimal for long-life, safety-critical 1.8V systems requiring both power and code supervision.

Availability

MAX6865UK17D4S+T is available at Aetrix Electronics and suitable for portable medical devices, battery-powered instrumentation, industrial sensor nodes, and low-power IoT endpoints requiring stable component supply across extended product lifecycles.

Supply support for MAX6865UK17D4S+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 industrial, medical, and communications markets.

The MAX6854–MAX6869 family delivers nanopower supervisory functionality targeting ultra-long-life portable electronics, with emphasis on guaranteed reset behavior under brownout and software fault conditions.

FAQ

What is the exact reset threshold voltage of the MAX6865UK17D4S+T?

The MAX6865UK17D4S+T has a factory-trimmed reset threshold of 1.665V, 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 "17" corresponds to 1.665V nominal. The device guarantees reset assertion when VCC falls below this threshold and remains asserted until VCC exceeds it plus hysteresis (0.5% of VTH).

Does the MAX6865UK17D4S+T require external components for basic operation?

No, the MAX6865UK17D4S+T operates autonomously with no external components required. Its internal 10kΩ MR pullup, factory-calibrated voltage reference, and integrated RC watchdog timer eliminate need for resistors, capacitors, or trimming. Only a 0.1µF ceramic bypass capacitor on VCC is recommended for noise suppression in noisy environments.

How does the watchdog timer in the MAX6865UK17D4S+T function, and what is its timeout?

The MAX6865UK17D4S+T watchdog timer expires after 3.3s (typical) if the WDI input remains static - either high or low - beyond that period. Any rising or falling edge on WDI clears the timer. The "S" suffix in the part number explicitly denotes the 3.3s timeout option (Table 3), distinct from the "L" option (209s). Timer operation is independent of VCC level within 1.2V–5.5V.

What is the reset timeout duration for the MAX6865UK17D4S+T, and is it adjustable?

The MAX6865UK17D4S+T has a fixed reset timeout of 1200ms minimum (D4 option), as indicated by the "D4" in its part number. This duration is factory-set and non-adjustable. It ensures sufficient hold time for µP initialization, PLL locking, and peripheral configuration before release - critical for reliable boot in resource-constrained systems.

Can the MAX6865UK17D4S+T operate reliably at very low supply voltages?

Yes, the MAX6865UK17D4S+T guarantees valid reset output down to VCC = 1.1V, as specified in the Electrical Characteristics table. Below this voltage, RESET may become indeterminate, but the device continues asserting reset until VCC rises above the 1.665V threshold plus hysteresis. This ensures fail-safe behavior during deep brownout recovery sequences.