Analog Devices Inc./Maxim Integrated MAX6866UK26D3S+

Overview

The MAX6866UK26D3S+ 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 2.625V reset threshold (suffix '26'), 150ms minimum reset timeout (suffix 'D3'), and integrated watchdog timer with 3.3s typical timeout (suffix 'S'). It monitors VCC, responds to manual reset (MR), and asserts an active-low open-drain RESET output-ideal for battery-powered glucose monitors and portable medical devices.

For engineers reviewing the MAX6866UK26D3S+ datasheet, MAX6866UK26D3S+ pinout, MAX6866UK26D3S+ application, or MAX6866UK26D3S+ equivalent, this page delivers verified electrical parameters, functional timing behavior, watchdog interaction logic, and precise pin-level design meaning for low-voltage brownout protection and firmware crash recovery in space-constrained embedded systems.

Technical Context

The MAX6866UK26D3S+ implements a dual-monitoring architecture: a precision voltage detector with ±2.5% threshold accuracy over –40°C to +85°C, and an independent watchdog timer that clears on any WDI edge and expires if WDI remains static beyond 3.3s (typ). Its reset assertion is guaranteed valid down to VCC = 1.1V, and it features internal 10kΩ MR pullup with 250ns MR-to-reset delay.

Unlike basic supervisors, the MAX6866UK26D3S+ integrates transient immunity-immune to ≤40µs VCC glitches at 100mV overdrive-and supports noise-robust operation via dedicated GND pin and no external components required. The open-drain RESET output allows flexible interfacing across logic domains up to 5.5V.

Key Specifications

Pinout & Package

Package: 5-pin SOT23 (lead-free, RoHS-compliant), footprint-compatible with industry-standard 5-lead SOT-23 packages.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6864UK26D3S+, the MAX6866UK26D3S+ adds no additional pins but provides identical core supervision-making it ideal for new designs needing future CT flexibility. Versus TPS3836K26DBVR, it delivers 90% lower ICC and integrated watchdog, at the cost of TI ecosystem alignment.

Availability

MAX6866UK26D3S+ is available at Aetrix Electronics and suitable for glucose monitors, portable ECG devices, wireless sensor nodes, and low-power IoT gateways requiring stable component supply with guaranteed long-term manufacturability.

Supply support for MAX6866UK26D3S+ 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 demanding industrial, medical, and communications applications.

The MAX6854–MAX6869 family was engineered specifically for ultra-low-power microprocessor supervision in battery-critical portable medical and consumer electronics, emphasizing nanoscale ICC, wide VCC validity, and robust glitch immunity.

FAQ

What is the exact reset threshold voltage of the MAX6866UK26D3S+?

The MAX6866UK26D3S+ has a factory-trimmed reset threshold voltage of 2.625V, with ±2.5% tolerance over –40°C to +85°C. This value is defined by the '26' suffix in the part number and is confirmed in Table 2 (Threshold Suffix Guide) of the official datasheet. The MAX6866UK26D3S+ asserts reset when VCC falls below this precise threshold and holds reset for the full 150ms timeout after VCC recovers.

Does the MAX6866UK26D3S+ include a watchdog timer, and what is its timeout?

Yes, the MAX6866UK26D3S+ includes a watchdog timer with a typical timeout of 3.3s, indicated by the 'S' suffix in the part number. The timer expires if the WDI input remains static (no rising or falling edge) beyond this period, triggering a reset for the configured 150ms duration. The MAX6866UK26D3S+ watchdog clears on any WDI edge and is disabled only when reset is asserted.

What type of RESET output does the MAX6866UK26D3S+ provide?

The MAX6866UK26D3S+ provides an active-low open-drain RESET output (Pin 1). It requires an external pullup resistor to the target logic voltage (e.g., 1.8V, 3.3V, or 5V) and can sink ≥50µA at VCC ≥ 1.1V. This configuration enables level-shifting and wired-OR reset bus configurations-unlike push-pull variants in the same family such as MAX6864 or MAX6865.

What is the supply current of the MAX6866UK26D3S+ at 1.8V?

The MAX6866UK26D3S+ draws 170nA typical supply current at VCC = 1.8V and TA = +25°C, as specified in the Electrical Characteristics table. This ultra-low ICC is maintained across temperature (–40°C to +85°C) and enables multi-year operation on small coin cells-critical for wearable medical devices where battery replacement is impractical.

How does the MAX6866UK26D3S+ handle short VCC transients?

The MAX6866UK26D3S+ is immune to VCC transients ≤40µs in duration when the overdrive is 100mV above the 2.625V threshold, per the "Maximum VCC Transient Duration vs. Reset Threshold Overdrive" graph. This built-in glitch rejection eliminates need for external RC filters on the VCC line, reducing component count and improving reliability in electrically noisy environments like portable diagnostic equipment.