LTC3407 Datasheet

• High Efficiency: Up to 96%
• Very Low Quiescent Current: Only 40µA
• 1.5MHz Constant Frequency Operation
• High Switch Current: 1A on Each Channel
• No Schottky Diodes Required
• Low R_DS(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: I_Q < 1µA
• Output Voltages from 5V down to 0.6V
• Power-On Reset Output
• Externally Sychronizable Oscillator
• Small Thermally Enhanced MSOP Package and 3mm x 3mm DFN Packages

• PDAs/Palmtop PCs
• Digital Cameras
• Cellular Phones
• Portable Media Players
• PC Cards
• Wireless and DSL Modems

The LTC3407 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 1.5MHz switching frequency, allowing the use of tiny, low cost capacitors and inductors 2mm or less in height. Each output voltage is adjustable from 0.6V to 5V. Internal synchronous 0.35Ω, 1A 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 ripple noise for low power efficiency. Burst Mode^® operation provides high efficiency at light loads, while pulse-skipping mode provides low ripple noise 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 <1μA.