The MC33464 series are micropower undervoltage sensing circuits that are specifically designed for use with battery powered microprocessor based systems, where extended battery life is required. A choice of several threshold voltages from 0.9 V to 4.5 V are available. These devices feature a very low quiescent bias current of 0.8 A typical. The MC33464 series features a highly accurate voltage reference, a comparator with precise thresholds and builtin hysteresis to prevent erratic reset operation, a choice of output configurations between open drain or complementary MOS, and guaranteed operation below 1.0 V with extremely low standby current. These devices are available in either SOT89 3pin or SOT23 5pin surface mount packages. Applications include direct monitoring of the MPU/logic power supply used in portable, appliance, automotive and industrial equipment.