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LTC3417A - Dual Synchronous 1.5A/1A 4MHz Step-Down DC/DC Regulator

The LTC3417A is a dual constant frequency, synchronous step-down DC/DC converter. Intended for medium power applications, it operates from a 2.25V to 5.5V input voltage range and has a constant programmable switching frequency, allowing the use of tiny, low cost capacitors and inductors 2mm or less in height. Each output voltage is adjustable from 0.8V to 5V. Internal, synchronous, low RDS(ON) power switches provide high efficiency without the need for external Schottky diodes.

A user selectable mode input allows the user to trade off ripple voltage for light load efficiency. Burst Mode® operation provides high efficiency at light loads, while Pulse Skip mode provides low ripple noise at light loads. A phase mode pin allows the second channel to operate in-phase or 180° out-of-phase with respect to channel 1. Out-ofphase operation produces lower RMS current on VIN and thus a lower RMS derating on the input capacitor.

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 125µA. In shutdown, the device draws <1µA.

Features High Efficiency: Up to 95% 1.5A/1A Guaranteed Minimum Output Current Synchronizable to External Clock No Schottky Diodes Required Programmable Frequency Operation: 1.5MHz or Adjustable From 0.6MHz to 4MHz Low RDS(ON) Internal Switches Short-Circuit Protected VIN: 2.25V to 5.5V Current Mode Operation for Excellent Line and Load Transient Response 125µA Quiescent Current in Sleep Mode Ultralow Shutdown Current: IQ < 1µA Low Dropout Operation: 100% Duty Cycle Power Good Output Phase Pin Selects 2nd Channel Phase Relationship with Respect to 1st Channel Internal Soft-Start with Individual Run Pin Control Available in Small Thermally Enhanced (5mm × 3mm) DFN and 20-Lead TSSOP Packages Typical Application

Applications GPS/Navigation Digital Cameras PC Cards Wireless and DSL Modems General Purpose Point of Load DC/DC Packaging

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