Analog Devices Inc./Maxim Integrated MAX706SCPA+

Overview

MAX706SCPA+ from Maxim Integrated is an active-low microprocessor supervisory circuit designed for +3V to +5V systems, providing power-on reset, watchdog timeout (1.6s), 2.93V supply-voltage monitoring, 1.25V power-fail comparator input, and debounced manual-reset input. It ensures reliable µP startup and brownout recovery in battery-powered portable instruments and embedded controllers.

For engineers reviewing the MAX706SCPA+ datasheet, MAX706SCPA+ pinout, MAX706SCPA+ application, or MAX706SCPA+ equivalent, this device serves as a precision voltage monitor with integrated watchdog and manual reset-key for critical power sequencing, low-battery warning, and fail-safe system initialization in space-constrained industrial and portable designs.

Technical Context

The MAX706SCPA+ implements a dedicated reset generator with 200ms guaranteed reset pulse width and guaranteed RESET assertion down to VCC = 1V. Its internal 2.93V threshold detector triggers reset during power-up, power-down, or brownout conditions, while the 1.25V PFI comparator enables external power-fail or low-battery detection via resistive divider.

A dedicated watchdog timer monitors WDI transitions and asserts WDO low after 1.6s timeout; unlike the AP/AR/AS/AT variants, the MAX706SCPA+ watchdog cannot be disabled. The MR input is TTL/CMOS-compatible with 500ns minimum pulse width at 3V and includes internal 70µA pullup.

Key Specifications

Pinout & Package

MAX706SCPA+ is housed in an 8-pin PDIP (Plastic Dual In-line Package) with 0.3-inch body width, lead-free compliant, and fully specified over 0°C to +70°C.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MAX706SEPA+ and MAX706SCSA+, the MAX706SCPA+ offers cost-effective commercial-temperature PDIP packaging ideal for bench testing and low-volume manufacturing-without sacrificing core supervision accuracy, watchdog reliability, or PFI comparator performance.

Availability

MAX706SCPA+ is available at Aetrix Electronics and suitable for battery-powered equipment, portable instruments, and embedded controllers requiring stable component supply across commercial temperature grades.

Supply support for MAX706SCPA+ 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) is a semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, computing, and communications markets.

The MAX706 family was designed specifically for cost-sensitive, space-constrained µP systems needing reliable power monitoring, reset generation, and watchdog supervision in +3V/+3.3V environments.

FAQ

What is the reset threshold voltage of the MAX706SCPA+?

The MAX706SCPA+ has a fixed reset threshold of 2.93V (VCC falling), with 20mV hysteresis. This value is factory-trimmed and guaranteed over temperature, ensuring consistent reset behavior for +3.3V µP systems. The threshold is not adjustable and applies regardless of supply voltage within the 2.7V–5.5V operating range. This specification is explicitly confirmed in the Electrical Characteristics table for MAX706S devices.

Does the MAX706SCPA+ include a watchdog timer, and can it be disabled?

Yes, the MAX706SCPA+ includes a watchdog timer with a nominal 1.6s timeout period triggered by WDI transitions. Unlike the MAX706AS/AT variants, the watchdog function in the MAX706SCPA+ cannot be disabled-it remains active whenever VCC is within specification. The timer resets on any WDI edge or during RESET assertion, and WDO goes low if no transition occurs within the timeout window.

What is the function of the PFI and PFO pins on the MAX706SCPA+?

The PFI (Power-Fail Input) pin connects to an external resistive divider to monitor voltages other than VCC-such as unregulated supplies or battery levels-and compares them against an internal 1.25V reference. When PFI falls below 1.25V, the PFO (Power-Fail Output) pin asserts low, enabling early-warning power-fail interrupts or low-battery alerts. PFO is an open-drain output capable of sinking ≥1.2mA.

Is the MAX706SCPA+ pin-compatible with other MAX706 variants like MAX706RCPA+ or MAX706TCPA+?

Yes, all MAX706x CPA+ variants-including MAX706RCPA+, MAX706SCPA+, and MAX706TCPA+-share identical 8-pin PDIP pinouts and core functionality. They differ only in reset threshold (2.63V, 2.93V, 3.08V respectively) and temperature grade. No PCB changes are needed when substituting between these parts, provided the target reset voltage matches system requirements.

What is the minimum VCC level at which the MAX706SCPA+ guarantees RESET assertion?

The MAX706SCPA+ guarantees RESET remains asserted (low) down to VCC = 1.0V at 0°C to +70°C, as confirmed in the Absolute Maximum Ratings and Functional Description sections. Below 1V, RESET becomes high-impedance. This ensures robust reset hold during severe brownout conditions, preventing µP execution in unstable voltage regions.