Maxim Integrated's MAX691EWE Microprocessor Supervisory Circuit

The MAX691EWE from Maxim Integrated is a highly integrated microprocessor (µP) supervisory circuit designed to monitor power supplies and microprocessor activity in digital systems. It provides excellent circuit reliability and low cost by eliminating external components and adjustments when used in conjunction with +5V-powered µPs.

This supervisory circuit features a combination of functions that make it ideal for microprocessor systems. It includes a precision voltage monitor, watchdog timer, µP reset, and battery backup switching circuitry. The device's main purpose is to ensure that the µP starts up in a known state and operates reliably, regardless of the conditions it encounters.

Key Features:

• Power Supply Monitoring: The MAX691EWE includes a precision voltage monitor that keeps a close eye on the +5V power supply. It ensures that the µP and other system components receive a stable and accurate voltage, which is critical for reliable operation.
• Watchdog Timer: An onboard watchdog timer ensures that the µP does not hang in an uncontrolled state. If the µP fails to reset the watchdog periodically, the MAX691EWE will issue a system reset, thereby ensuring proper system operation.
• µP Reset: The device generates a reset pulse whenever the monitored power supply falls below a preset threshold or if the watchdog timer times out. This reset output can reset the µP as well as other system components.
• Battery Backup: The MAX691EWE features battery backup switching circuitry that automatically switches to a backup battery when the main power supply fails, ensuring uninterrupted operation of critical system functions.

Applications:

The MAX691EWE is suitable for use in a wide range of applications that require robust power supply monitoring and µP supervision. These include:

• Computers and Controllers
• Intelligent Instruments
• Critical µP Power Monitoring
• Portable/Battery-Powered Equipment

With its compact 16-SO Wide package, the MAX691EWE is designed for space-constrained applications, offering a comprehensive solution for power management and µP supervision in a single IC. Maxim Integrated's commitment to quality ensures that this supervisory circuit meets the high reliability standards required for today's sophisticated electronic systems.