Microprocessor Supervisory ICs

ADM690-699 monitor the μP's supply, perform Reset and Backup tasks when it drops. And they do it FAST

Microprocessor supervisory circuits are the unsung heroes of digital equipment and systems. They detect when the power supply voltage is dropping during a power failure or brownout and take action to write-protect memory and switch to battery backup — or at least send a Reset signal to the processor. Read full article