The LTC3456 is a complete power management system IC optimized for a variety of portable applications. The device generates two separate power rails: a 3.3V (fixed) Main supply and a 1.8V (adjustable) Core supply. In addition, the LTC3456 contains a USB power manager, a Hot Swap output, a low-battery indicator and an alwaysalive VMAX output. The LTC3456 takes power from one of three sources: a Wall adapter, a USB port or a 2-cell Alkaline/NiCd/NiMH battery, in that order of priority. Current drawn from the USB port is accurately limited to 100mA or 500mA based on the state of the USBHP pin.