Analog Devices Inc./Maxim Integrated MAX6866UK29D3S+T

Overview

The MAX6866UK29D3S+T from Maxim Integrated is a nanopower microprocessor supervisory circuit in a 5-pin SOT23 package, featuring voltage monitoring, manual reset input (MR), and watchdog timer (WDI) with 209s typical timeout. It asserts an active-low open-drain RESET output when VCC drops below 2.925V (±2.5%), MR is pulled low, or WDI stalls beyond timeout. Designed for ultra-low-power battery-operated systems like glucose monitors and portable medical devices.

For engineers reviewing the MAX6866UK29D3S+T datasheet, MAX6866UK29D3S+T pinout, MAX6866UK29D3S+T application, or MAX6866UK29D3S+T equivalent, this page delivers verified electrical specs, validated SOT23-5 terminal mapping, confirmed 2.925V reset threshold and 209s watchdog timeout, and two field-tested alternative parts with documented functional trade-offs.

Technical Context

This device integrates a precision bandgap-based voltage monitor with hysteresis (0.5% of VTH), a monostable watchdog timer cleared by WDI edges, and a manual reset path with 250ns MR-to-RESET delay. The internal 10kΩ MR pullup enables direct switch interface without external components.

The open-drain RESET output supports level-shifting across 0–5.5V logic domains and remains valid down to VCC = 1.1V. Immunity to sub-40µs VCC transients at 100mV overdrive ensures robust operation in noisy supply environments.

Key Specifications

Pinout & Package

Package: 5-pin SOT23-5, lead-free, surface-mount, 2.9mm × 1.6mm footprint.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX6866UK29D3S+T, MAX6864UK29D3S+T offers identical supervision timing but constrains RESET interface flexibility, while TPS3838K29DBVR sacrifices nanopower operation and watchdog safety for broader TI ecosystem compatibility.

Availability

MAX6866UK29D3S+T is available at Aetrix Electronics and suitable for glucose monitors, patient monitors, smart wearables, and industrial handheld terminals requiring stable component supply across extended production lifecycles.

Supply support for MAX6866UK29D3S+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, sensing, and connectivity applications in industrial, medical, and consumer markets.

The MAX6854–MAX6869 family delivers nanopower supervisory functions targeting battery-constrained medical and portable electronics, emphasizing ultra-low ICC, wide VCC range, and integrated watchdog safety.

FAQ

What is the exact reset threshold voltage of the MAX6866UK29D3S+T?

The MAX6866UK29D3S+T has a factory-trimmed reset threshold voltage of 2.925V with ±2.5% tolerance over temperature. This value is confirmed in Table 2 (Threshold Suffix Guide) of the datasheet, where suffix "29" corresponds to 2.925V nominal. The device asserts RESET when VCC falls below this threshold and holds it for the 150ms minimum timeout period after VCC recovers.

Does the MAX6866UK29D3S+T include a watchdog timer, and what is its timeout?

Yes, the MAX6866UK29D3S+T includes a watchdog timer with a typical timeout of 209s, denoted by the "S" suffix in the part number. The timer is cleared on any rising or falling edge at the WDI pin and expires only if WDI remains static longer than this period. This long timeout is optimized for low-duty-cycle firmware supervision in medical and portable equipment.

What type of RESET output does the MAX6866UK29D3S+T provide?

The MAX6866UK29D3S+T provides an active-low open-drain RESET output (Pin 1). It requires an external pullup resistor to a logic-compatible voltage (0–5.5V) and can interface across mixed-voltage domains. Unlike push-pull variants, this configuration supports wired-OR reset buses and level shifting without additional components.

What is the supply current consumption of the MAX6866UK29D3S+T at room temperature?

The MAX6866UK29D3S+T draws 170nA typical supply current (ICC) at +25°C with VCC = 2.5V and no load on RESET. This ultra-low quiescent current is measured under normal operating conditions (VCC > VTH, reset deasserted) and is critical for extending battery life in always-on portable medical devices.

How is the reset timeout period configured on the MAX6866UK29D3S+T?

The MAX6866UK29D3S+T has a fixed reset timeout period of 150ms minimum (suffix "D3"), as defined in Table 4 of the datasheet. Unlike the MAX6861–MAX6863 series, it does not feature a CT pin for dynamic selection - the D3 option is factory-set and non-adjustable. This ensures predictable reset hold time across all operating conditions.