Analog Devices Inc./Maxim Integrated MAX706AREUA+

Overview

MAX706AREUA+ from Maxim Integrated is an active-low microprocessor supervisory circuit in 8-pin µMAX package, providing precision +3V supply monitoring (2.63V reset threshold), 200ms reset pulse width, 1.6s watchdog timeout, and 1.25V power-fail comparator input-designed for reliable reset assertion during brownout in battery-powered portable instruments and embedded controllers.

For engineers reviewing the MAX706AREUA+ datasheet, MAX706AREUA+ pinout, MAX706AREUA+ application, or MAX706AREUA+ equivalent, this device delivers verified voltage supervision, manual reset debouncing, low-quiescent-current operation (100µA), and guaranteed RESET assertion down to VCC = 1V-critical for low-power, space-constrained designs requiring deterministic startup and fault recovery.

Technical Context

The MAX706AREUA+ implements a precision bandgap-based reset generator with 20mV hysteresis and a dedicated 1.25V reference for the PFI comparator. Its watchdog timer resets on WDI edge transitions and asserts WDO low after 1.6s timeout-disabled automatically when WDI is left open or driven high-impedance (≤600nA leakage).

It features TTL/CMOS-compatible MR input with 500ns minimum pulse width at 3V, internal 70µA MR pullup, and dual-output logic compatibility: active-low RESET and open-drain PFO with 1.2mA sink capability. All functions operate across –40°C to +85°C with VCC from 2.7V to 5.5V.

Key Specifications

Pinout & Package

MAX706AREUA+ is housed in an 8-pin µMAX package (U8-1), 3mm × 3mm, exposed pad, lead-free, surface-mountable with 0.5mm pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX706RCSA+, MAX706AREUA+ offers 30% smaller board area and better thermal performance; compared with TPS3808G12DBVR, it adds critical watchdog and power-fail monitoring at the cost of 65µA higher quiescent current-justified in safety-critical or battery-backed systems requiring full supervision.

Availability

MAX706AREUA+ is available at Aetrix Electronics and suitable for battery-powered equipment, portable instruments, and industrial controllers requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for MAX706AREUA+ 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, computing, and communications markets.

The MAX706 family delivers low-cost, integrated µP supervision-including reset, watchdog, and power-fail detection-for space- and power-constrained embedded systems operating from +3V/+3.3V supplies.

FAQ

What is the reset threshold voltage of the MAX706AREUA+?

The MAX706AREUA+ has a fixed reset threshold of 2.63V (VCC falling), with 20mV hysteresis. This value is factory-trimmed and guaranteed over –40°C to +85°C. It ensures reliable reset assertion before most +3.3V microprocessors enter undefined operation, and is identical to the MAX706R and MAX706AR variants. The threshold is not adjustable and applies only to the VCC supply monitored by the device.

Does the MAX706AREUA+ include a watchdog timer?

Yes, the MAX706AREUA+ includes a watchdog timer with a nominal timeout period of 1.6 seconds. The timer resets on any edge transition at the WDI pin and asserts the WDO output low if no transition occurs within that window. Unlike the MAX706R/S/T variants, the MAX706AREUA+ (as part of the MAX706AR/AS/AT series) automatically disables the watchdog when WDI is left open or driven high-impedance with leakage <600nA.

What is the function of the PFI and PFO pins on the MAX706AREUA+?

The PFI (Power-Fail Input) pin connects to an external resistive divider to monitor a secondary voltage rail or battery level. It compares the applied voltage against an internal 1.25V reference. When PFI falls below 1.25V, the PFO (Power-Fail Output) pin-configured as an active-low open-drain output-asserts low, enabling early-warning interrupts or controlled shutdown. PFO can sink ≥1.2mA and is electrically independent of the RESET function.

Can the MAX706AREUA+ operate from a +5V supply?

Yes, the MAX706AREUA+ operates across a VCC range of 2.7V to 5.5V, fully specified at both +3.3V and +5V. At +5V, electrical parameters shift slightly: MR minimum pulse width reduces to 150ns, output drive improves (e.g., VOL ≤0.4V at 3.2mA sink), and supply current remains ≤100µA. The 2.63V reset threshold remains unchanged, making it suitable for mixed-supply systems where the µP runs at +5V but supervision targets a +3.3V domain.

What package type is used for the MAX706AREUA+?

The MAX706AREUA+ is supplied in an 8-pin µMAX package (package code U8-1), measuring 3mm × 3mm with 0.5mm lead pitch and an exposed thermal pad. It is a surface-mount, lead-free package optimized for high-density PCB layouts. The µMAX footprint differs significantly from SO-8 and PDIP packages-pin 1 is marked by a dot, and pin 8 is NC (no connection), requiring careful layout verification against the official Maxim package drawing.