The LTC699 provides power supply monitoring for microprocessor-based systems. The features include microprocessor reset and watchdog timing. Precise internal voltage reference and comparator circuit monitor the power supply line. When an out-of-tolerance condition occurs, the RESET output is forced to active low. In addition, the RESET output is guaranteed to remain logic low even with VCC as low as 1V. An internal watchdog timer is also available, which forces the RESET output to active low when the watchdog input is not toggled prior to the time-out period of 1.6 seconds.