The MAX691EJE from Maxim Integrated is a comprehensive microprocessor (µP) supervisory circuit that provides several essential functions for µP system monitoring. This integrated circuit (IC) ensures that the µP and its associated hardware are reset to a known, stable state upon power-up, power-down, or during a brownout condition. It is an essential component for systems that require high reliability and resilience.

Key Features

• Power Supply Monitoring: The MAX691EJE continuously monitors the power supply voltage and ensures that the system has a stable power supply before the µP is allowed to operate. This prevents the µP from running with insufficient power that could lead to unpredictable behavior.
• Power-On Reset: Upon power-up, the IC generates a reset pulse to initialize the µP correctly. This reset pulse is maintained for a sufficient duration to allow the power supply and µP to stabilize.
• Battery Backup Switching: This device can automatically switch to a backup battery when the primary power supply fails, ensuring uninterrupted operation of critical system functions.
• Memory Write Protection: During power failures or brownout conditions, the MAX691EJE protects against erroneous writes to memory by disabling write operations, thus preserving data integrity.
• Watchdog Timer: A built-in watchdog timer ensures that the µP is operating correctly. If the µP fails to provide a periodic signal to the timer, the MAX691EJE will issue a reset signal to the µP to recover from any potential hang-up or malfunction.

Applications

With its robust feature set, the MAX691EJE is ideal for critical applications where system reliability cannot be compromised. It is widely used in:

• Computers and Controllers
• Intelligent Instruments
• Portable/Battery-Powered Equipment
• Industrial Systems
• Communication Devices

Package and Availability

The MAX691EJE is packaged in a 16-pin JEDEC standard configuration, which makes it easy to integrate into a wide variety of system designs. It is available for ordering from Maxim Integrated and its authorized distributors, ensuring that designers can incorporate this critical supervisory function into their systems with ease.