The MAX696/MAX697 supervisory circuits reduce the complexity and number of components required for power-supply monitoring and battery-control functions in microprocessor (µP) systems. These include µP reset and backup-battery switchover, watchdog timer, CMOS RAM write protection, and power-failure warning. The MAX696/MAX697 significantly improve system reliability and accuracy compared to that obtained with separate ICs or discrete components.The MAX696 and MAX697 are supplied in 16-pin packages and perform six functions:A reset output during power-up, power-down, and brownout conditions. The threshold for this "lowline" reset is adjustable by an external voltage-divider.A reset pulse if the optional watchdog timer has not been toggled within a specified time.Individual outputs for low-line and watchdog fault conditions.The reset time may be left at its default value of 50ms, or may be varied with an external capacitor or clock pulses.A separate 1.3V threshold detector for power-fail warning, low-battery detection, or to monitor a power supply other than VCC.The MAX696 also has battery-backup switching for CMOS RAM, CMOS microprocessor, or other low-power logic.The MAX697 lacks battery-backup switching, but has write-protection pins (active-low CE IN and active-low CE OUT) for CMOS RAM or EPROM. In addition, it consumes less than 250 microamperes.ApplicationsComputersControllersCritical µP Power MonitoringIntelligent Instruments