LTC3448

U U FEATURES ■ High Efficiency: Up to 96% ■ Very Low Quiescent Supply Current: 32µA During Linear Regulator Operation ■ 600mA Output Current (Buck Converter) ■ Optionally Operates as Linear Regulator Below 3mA—External or Automatic ON/OFF ■ 2.5V to 5.5V Input Voltage Range ■ 1.5MHz or 2.25MHz Constant Frequency Operation or External Synchronization ■ No Schottky Diode Required ■ Low Dropout Operation: 100% Duty Cycle ■ 0.6V Reference Allows Low Output Voltages ■ Shutdown Mode Draws < 1µA Supply Current ■ Current Mode Operation for Excellent Line and Load Transient Response ■ Overtemperature Protected ■ Low Profile (3mm × 3mm) 8-Lead DFN and 8-Lead MSOP Packages U APPLICATIO S ■ Cellular Telephones ■ Personal Information Appliances ■ Wireless and DSL Modems ■ Digital Still Cameras ■ MP3 Players ■ Portable Instruments , LTC and LT are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents including 5481178, 6580258, 6304066, 6127815, 6498466, 6611131. Others pending. LTC3448 1.5MHz/2.25MHz, 600mA Synchronous Step-Down Regulator with LDO Mode DESCRIPTIO The LTC®3448 is a high efficiency, monolithic, synchronous buck regulator using a constant frequency, current mode architecture. Supply current during operation is only 32µA (linear regulator mode) and drops to <1µA in shutdown. The 2.5V to 5.5V input voltage range makes the LTC3448 ideally suited for single Li-Ion battery-powered appli...