With a typical power consumption of 11 µA, the S-8430AF step-up switching and step-down series voltage regulator is designed to maximize battery life for cellular telephones, handheld terminals, notebook computers, PDAs, and other battery-powered products. The IC consists of an RC oscillator, a switching regulator, a voltage regulator, and a Schottky diode. With input voltage of 0.9V to 12V, selectable output voltage is 3V or 5V. The 40-kHz RC oscillator operates as a series voltage regulator when input voltage is higher than output voltage and as a step-up switching regulator and a voltage regulator when input voltage is lower than output voltage. This dual functionality keeps the output level constant over a wide range of input voltages.