LTC3407EMSE-4#PBF

LTC3407-4 Dual Synchronous, 800mA, 2.25MHz Step-Down DC/DC Regulator DESCRIPTION FEATURES n n n n n n n n n n n n n n High Efficiency: Up to 95% Very Low Quiescent Current: Only 40μA 2.25MHz Constant Frequency Operation High Switch Current: 1.2A on Each Channel No Schottky Diodes Required Low RDS(ON) Internal Switches: 0.35Ω Current Mode Operation for Excellent Line and Load Transient Response Short-Circuit Protected Low Dropout Operation: 100% Duty Cycle Ultralow Shutdown Current: IQ < 1μA Output Voltages from 5V down to 0.6V Power-On Reset Output Externally Synchronizable Oscillator Small Thermally Enhanced MSOP and 3mm × 3mm DFN Packages APPLICATIONS n n n n n n PDAs/Palmtop PCs Digital Cameras Cellular Phones Portable Media Players PC Cards Wireless and DSL Modems The LTC®3407-4 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, 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 life, 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