LTC3405A-1.8

LTC3405A-1.5/LTC3405A-1.8 1.5V, 1.8V, 1.5MHz, 300mA Synchronous Step-Down Regulators in ThinSOT U U FEATURES ■ High Efficiency: Up to 93% ■ Very Low Quiescent Current: Only 20µA During Operation ■ 300mA Output Current at VIN = 3V ■ 2.5V to 5.5V Input Voltage Range ■ 1.5MHz Constant Frequency Operation ■ No Schottky Diode Required ■ Low Dropout Operation: 100% Duty Cycle ■ Stable with Ceramic Capacitors ■ Shutdown Mode Draws < 1µA Supply Current ■ ±3% Output Voltage Accuracy ■ Current Mode Operation for Excellent Line and Load Transient Response ■ Overtemperature Protected ■ Low Profile (1mm) ThinSOTTM Package U APPLICATIO S ■ Cellular Telephones ■ Personal Information Appliances ■ Wireless and DSL Modems ■ Digital Still Cameras ■ MP3 Players ■ Portable Instruments TYPICAL APPLICATIO VIN 2.7V TO 5.5V CIN** 4.7µF CER 4 VIN 3 4.7µH* SW LTC3405A-1.8 1 RUN 6 5 MODE VOUT GND 2 3405A1518 F01 *MURATA LQH3C4R7M34 **TAIYO YUDEN JMK212BJ475MG VOUT 1.8V 300mA COUT** 4.7µF CER Figure 1a. High Efficiency Step-Down Converter DESCRIPTIO The LTC®3405A-1.5/LTC3405A-1.8 are high efficiency monolithic synchronous buck regulators using a constant frequency, current mode architecture. Supply current during operation is only 20µA and drops to <1µA in shutdown. The 2.5V to 5.5V input voltage range makes the LTC3405A-1.5/LTC3405A-1.8 ideally suited for single Li-Ion battery-powered applications. 100% duty cycle provides low dropout operation, extending battery life in portable syste...