The LTC3556 is a highly integrated power management and battery charger IC for Li-Ion/Polymer battery applications. It includes a high efficiency current limited switching PowerPath manager with automatic load prioritization, a battery charger, an ideal diode, and three synchronous switching regulators (two bucks and one buck-boost). Designed specifically for USB applications, the LTC3556’s switching power manager automatically limits input current to a maximum of either 100mA or 500mA for USB applications or 1A for adapter-powered applicationsThe LTC3556’s switching input stage transmits nearly all of the 2.5W available from the USB port to the system load with minimal power wasted as heat. This feature allows the LTC3556 to provide more power to the application and eases the constraint of thermal budgeting in small spaces. The two buck regulators can provide up to 400mA each and the buck-boost can deliver 1A..The LTC3556 is available in the low profile 28-pin (4mm × 5mm × 0.75mm) QFN surface mount package.ApplicationsHDD-Based MP3 Players, PDAs, GPS, PMPsOther USB-Based Handheld Products