LTC3250-1.2

LTC3250-1.5/LTC3250-1.2 High Efficiency, Low Noise, Inductorless Step-Down DC/DC Converter U U FEATURES s 2.7V to 5.5V Input Voltage Range s No Inductors s Li-Ion (3.6V) to 1.5V with 81% Efficiency s Low Noise Constant Frequency Operation s Output Voltages: 1.5V ±4%, 1.2V ±4% s Output Current: 250mA s Shutdown Disconnects Load from VIN s Low Operating Current: IQ = 35µA s Low Shutdown Current: ISD < 1µA s Oscillator Frequency = 1.5MHz s Soft-Start Limits Inrush Current at Turn-On s Short-Circuit and Overtemperature Protected s Low Profile (1mm) SOT-23 Package U APPLICATIO S s Handheld Computers s Cellular Phones s Digital Cameras s Handheld Medical Instruments s Low Power DSP Supplies DESCRIPTIO The LTC®3250-1.5/LTC3250-1.2 are charge pump stepdown DC/DC converters that produce a 1.5V or 1.2V regulated output from a 2.7V to 5.5V input. The parts use switched capacitor fractional conversion to achieve typical efficiency two times higher than that of a linear regulator. No inductors are required. A unique constant frequency architecture provides a low noise regulated output as well as lower input noise than conventional charge pump regulators.* High frequency operation (fOSC = 1.5MHz) simplifies filtering to further reduce conducted noise. The part also uses Burst Mode® operation to improve efficiency at light loads. Low operating current (35µA with no load, <1µA in shutdown) and low external parts count (three small ceramic capacitors) make the LTC3250-1.5/LTC3250-1.2 ideal...