LTC3417A-1

The LTC3417A-1 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 R_DS(ON) power switches provide high efficiency without the need for external Schottky diodes.

The open drain POR pin goes low when either output voltage falls 6% below regulation. The output will remain low 150ms longer than the duration of the out of regulation condition.

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-of-phase operation produces lower RMS current on V_IN and thus lower stress 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 100μA. In shutdown, the device draws <1μA.

Applications

• GPS/Navigation Systems
• Automotive Instrumentation
• PC Cards
• Industrial Power Supplies
• General Purpose Point of Load DC/DC