LTC3548-1 Datasheet | Linear Technology

Features n High Efficiency: Up to 95% n 1.8V at 800m A/1.575V at 400m A n Very Low Quiescent Current: Only 40μA n 2.25MHz Constant-Frequency Operation n High Switch Current: 1.2A and 0.7A n No Schottky Diodes Required n VIN: 2.5V to 5.5V n Current Mode Operation for Excellent Line and Load Transient Response n Short-Circuit Protected n Low Dropout Operation: 100% Duty Cycle n Ultralow Shutdown Current: IQ < 1μA n Small Thermally Enhanced 3mm × 3mm DFN Packages APPLICATIONS n PDAs/Palmtop PCs n Digital Cameras n Cellular Phones n Portable Media Players n PC Cards n Wireless and DSL Modems Dual Synchronous, Fixed Output 2.25MHz Step-Down DC/DC Regulator DESCRIPTION The LTC®3548-1 is a dual, fixed output, constant-frequency, synchronous step-down DC/DC converter. Intended for low power applications, it operates from 2.5V to 5.5V input voltage range and has a constant 2.25MHz switching frequency, allowing the use of tiny, low cost capacitors and inductors with a profile ≤1mm. The output voltage for channel 1 is fixed at 1.8V and for channel 2 is fixed at 1.575V. Internal synchronous 0.35Ω, 1.2A/0.7A power switches provide high efficiency without the need for external Schottky diodes. Burst Mode® operation provides high efficiency at light loads. To further maximize battery runtime, the P-channel MOSFETs are turned on continuously in dropout (100% duty cycle), and both channels draw a total quiescent current of only 40μA. In shutdown, the device draws <1μA. The LTC3548-1 is available in both thin (0.75mm) and ultrathin (0.55mm) 3mm × 3mm DFN packages. L, LT, LTC, LTM, Linear Technology, the Linear logo and Burst Mode are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Protected by U.S. Patents, including 5481178, 6127815, 6304066, 6498466, 6580258 6611131.. TYPICAL APPLICATION VIN 2.7V TO 5.5V VOUT2 1.575V 400m A COUT2 10μF CER CIN 10μF CER 4.7μH CFF2 330p F VIN RUN1...