Maxim Integrated MAX691EEWE Microprocessor Supervisory Circuit

The MAX691EEWE from Maxim Integrated is a sophisticated 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 device ensures that the µP is properly reset upon power-up by monitoring the supply voltage and asserting a reset if it is not within acceptable limits. The reset signal remains asserted for at least 140ms after the supply voltage reaches the reset voltage threshold, ensuring the µP starts up in a known state every time. Additionally, the MAX691EEWE includes a debounced manual push-button reset input, allowing for a simple and effective way to manually reset the system whenever necessary.

One of the key features of the MAX691EEWE is its watchdog timer, which keeps the µP from running amok during a malfunction. If the µP fails to provide a periodic signal to the MAX691EEWE, the watchdog timer will time out and generate a system reset. This helps to maintain system integrity and prevent data corruption.

The MAX691EEWE also offers a 1.25V threshold detector for power-fail warning, low-battery detection, or to monitor a power supply other than +5V. This feature is particularly useful for battery-powered applications where it is critical to detect low battery conditions to prevent data loss or hardware damage.

This device is available in a 16-pin Wide SO package and is specified over the commercial temperature range. Its compact size and comprehensive feature set make the MAX691EEWE an ideal choice for use in systems that require reliable operation, such as portable computers, controllers, and intelligent instruments.

With its combination of power-supply monitoring, microprocessor monitoring, and watchdog timer functionality, the Maxim Integrated MAX691EEWE provides a high level of protection for digital systems, ensuring stable and reliable operation even in the face of power supply variability or system errors.