The MB3793 is an integrated circuit to monitor power voltage; it incorporates a watchdog timer. A reset signal is output when the power is cut or falls abruptly. When the power recovers normally after resetting, a power-on reset signal is output to microprocessor units (MPUs). An internal watchdog timer with two inputs for system operation diagnosis can provide a fall-safe function for various applicaiton systems. There is also a mask option that can detect voltages of 4.9 to 2.4 V in 0.1-V steps.