Maxim Integrated MAX699CPA Microprocessor Supervisory Circuit

The MAX699CPA from Maxim Integrated is a highly reliable microprocessor (µP) supervisory circuit designed to monitor power supplies in digital systems. It provides excellent circuit reliability and low cost by eliminating external components and adjustments when used with +5V-powered circuits.

This device significantly improves system reliability by monitoring the power supply voltage and ensuring that the microprocessor is reset to a known state during power-up, power-down, and brown-out conditions. The MAX699CPA includes a variety of features that make it an essential component for any system requiring a stable and reliable operation.

Key Features:

• Precision Voltage Monitoring: The MAX699CPA keeps a watchful eye on the system voltage levels, and if a drop below a preset threshold is detected, it will assert a reset signal to prevent system errors.
• Power-On Reset: Upon power-up, the device ensures that the µP starts operating in a predictable state by asserting a reset signal for a minimum of 240ms after the power supply has stabilized.
• Manual Reset Capability: A manual reset input allows for a reset to be triggered with an external pushbutton or logic signal, providing an additional layer of system control.
• Watchdog Timer: The integrated watchdog timer requires periodic servicing by the µP, and if it's not serviced within a preset time frame, it will issue a system reset, ensuring the system does not hang due to software anomalies.
• Battery Backup Switching: In the event of a power failure, the MAX699CPA can automatically switch to a backup battery to maintain system operation without interruption.

This supervisory circuit is available in an 8-pin PDIP package, making it suitable for through-hole mounting, and it operates over a wide temperature range from 0°C to +70°C. Its low supply current of 1.5mA (typical) makes it an energy-efficient choice for portable and battery-powered applications.

The MAX699CPA is an indispensable component for ensuring the integrity of microprocessor systems in a wide range of applications, including computers, controllers, intelligent instruments, and critical µP power monitoring. By providing reliable reset and monitoring functions, it helps maintain the overall health and stability of electronic systems.