The LTC4156 is a 15 watt I2C controlled power manager with PowerPath™instant-on operation, high efficiency switching battery charging and USB compatibility. The LTC4156 seamlessly manages power distribution from two 5V sources, such as a USB port and a wall adapter, to a single-cell rechargeable lithium iron phosphate battery and a system load.The LTC4156’s switching battery charger automatically limits its input current for USB compatibility, or may draw up to 3A from a high power wall adapter. The high efficiency step-down switching charger is designed to provide maximum power to the application and reduced heat in high power density applications.I2C adjustability of input current, charge current, battery float voltage, charge termination, and many other parameters allows maximum flexibility. I2C status reporting of key system and charge parameters facilitates intelligent control decisions. USB On-The-Go support provides 5V power back to the USB port without any additional components. A dual-input, priority multiplexing, overvoltage protection circuit guards the LTC4156 from high voltage damage on the VBUSpin.The LTC4156 is available in the low profile (0.75mm) 28-lead 4mm × 5mm QFN surface mount package.ApplicationsPortable Medical DevicesPortable Industrial DevicesBackup Devices