The IMP690A/IMP692A/IMP802L/IMP802M/IMP805L simplify power supply monitoring and control in microprocessor systems. Each circuit implements four functions: Reset control, watchdog monitoring, batterybackup switching and power-failure monitoring. In addition to microprocessor reset under powerup and power-down conditions, these devices provide battery-backup switching to maintain control in powerloss and brown-out situations. Additional monitoring capabilities can provide an early warning of unregulated power-supply loss before the voltage regulator drops out. The important features of these four functions are: