LTC3561

U U FEATURES ■ Uses Tiny Capacitors and Inductor ■ High Frequency Operation: Up to 4MHz ■ High Switch Current: 1.4A ■ Low RDS(ON) Internal Switches: 0.110Ω ■ High Efficiency: Up to 95% ■ VIN: 2.63V to 5.5V ■ Stable with Ceramic Capacitors ■ Current Mode Operation for Excellent Line and Load Transient Response ■ Short-Circuit Protected ■ Low Dropout Operation: 100% Duty Cycle ■ Low Shutdown Current: IQ ≤ 1µA ■ Low Quiescent Current: 240µA ■ Output Voltages from 0.8V to 5V ■ Low Noise Pulse-Skipping Operation ■ Small 8-Pin DFN Package U APPLICATIO S ■ Wireless LAN Power ■ Notebook Computers ■ Digital Cameras ■ Cellular Phones ■ Board Mounted Power Supplies LTC3561 1A, 4MHz, Synchronous Step-Down DC/DC Converter DESCRIPTIO The LTC®3561 is a constant-frequency, synchronous, step-down DC/DC converter. Intended for medium power applications, it operates from a 2.63V to 5.5V input voltage range and has a user configurable operating frequency up to 4MHz, allowing the use of tiny, low cost capacitors and inductors 2mm or less in height. The output voltage is adjustable from 0.8V to 5V. Internal synchronous 0.11Ω power switches with 1.4A peak current ratings provide high efficiency. The LTC3561’s current mode architecture and external compensation allow the transient response to be optimized over a wide range of loads and output capacitors. To further maximize battery life, the P-channel MOSFET is turned on continuously in dropout (100% duty cycle). The no-load quiescent current is o...