LTC3410B 2.25MHz, 300mA Synchronous Step-Down Regulator in SC70 UFEATURESDESCRIPTIO ■ High Efficiency: Up to 96% The LTC®3410B is a high efficiency monolithic synchro- ■ 300mA Output Current at VIN = 3V nous buck regulator using a constant frequency, current ■ 380mA Minimum Peak Switch Current mode architecture. The device is available in adjustable ■ 2.5V to 5.5V Input Voltage Range and fixed output voltage versions. Supply current during ■ 2.25MHz Constant Frequency Operation operation is only 200µA, dropping to <1µA in shutdown. ■ No Schottky Diode Required The 2.5V to 5.5V input voltage range makes the LTC3410B ■ Low Dropout Operation: 100% Duty Cycle ideally suited for single Li-Ion battery-powered applica- ■ Stable with Ceramic Capacitors tions. 100% duty cycle provides low dropout operation, ■ 0.8V Reference Allows Low Output Voltages extending battery life in portable systems. PWM pulse ■ Shutdown Mode Draws < 1µA Supply Current skipping mode operation provides very low output ripple ■ ±2% Output Voltage Accuracy voltage for noise sensitive applications. ■ Current Mode Operation for Excellent Line and Load Transient Response Switching frequency is internally set at 2.25MHz, allowing ■ Overtemperature Protected the use of small surface mount inductors and capacitors. ■ Available in Low Profile SC70 Package The LTC3410B is specifically designed to work well with ceramic output capacitors, achieving very low output U voltage ripple and a small PCB footprint. APPLICATIO S The internal synchronous switch increases efficiency and ■ Cellular Telephones eliminates the need for an external Schottky diode. Low ■ Personal Information Appliances output voltages are easily supported with the 0.8V feed- ■ Wireless and DSL Modems back reference voltage. The LTC3410B is available in a ■ Digital Still Cameras tiny, low profile SC70 package. ■ MP3 Players , LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All ■ Portable Instruments other trademarks are the property of their respective owners. Protected by U.S. Patents, including 5481178, 5994885, 6580258, 6304066, 6127815, 6498466, 6611131. UTYPICAL APPLICATIOEfficiency and Power Lossvs Output Current 100 1 90 EFFICIENCY V 4.7µH IN V 80 2.7V V OUT 0.1 IN SW 1.2V POWER LOSS (W) TO 5.5V C 10pF 70 IN C 2.2µF LTC3410B OUT 2.2µF 60 CER RUN CER 50 0.01 VFB POWER LOSS 232k 40 GND EFFICIENCY (%) 464k 30 0.001 3410 TA01 20 VIN = 2.7V 20 VIN = 3.6V VIN = 4.2V 0.0001 0 1 10 100 1000 OUTPUT CURRENT (mA) 3410 TA01b 3410bfa 1