LTC3548 Datasheet | Linear Technology

Dual Synchronous, 400m A/800m A, 2.25MHz Step-Down DC/DC Regulator Features n High Efficiency: Up to 95% n Very Low Quiescent Current: Only 40μA n Low Output Ripple Burst Mode® Operation n 2.25MHz Constant-Frequency Operation n High Switch Current: 0.7A and 1.2A n No Schottky Diodes Required n Low RDS(ON) Internal Switches: 0.35Ω 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 Output Voltages from 5V down to 0.6V n Power-On Reset Output n Externally Synchronizable Oscillator n Small Thermally Enhanced MSOP and 3mm × 3mm DFN Packages APPLICATIONS - PDAs/Palmtop PCs - Digital Cameras - Cellular Phones - Portable Media Players - PC Cards - Wireless and DSL Modems DESCRIPTION The LTC®3548 is a dual, 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. Each output voltage is adjustable from 0.6V to 5V. Internal synchronous 0.35Ω, 0.7A/1.2A power switches provide high efficiency without the need for external Schottky diodes. A user selectable mode input is provided to allow the user to trade-off noise ripple for low power efficiency. Burst Mode operation provides high efficiency at light loads, while pulse-skipping mode provides low noise ripple 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. 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,...