Dual USB/wall adapter Li-ion battery charger with gas gauge

Description
The STw4102 is a standalone constant current constant voltage (CCCV) linear charger specifically designed for Li-ion batteries.
The STw4102 offers dual charging capability using separate inputs for USB cable and wall adapter, or a single input that accepts both.
The STw4102 also offers programmable fast charge current using an external resistor. A thermal regulation circuit limits the charge current against the die high power dissipation or high ambient temperature. An end of charge output pin indicates the charge termination when the fast charge current drops below 10% of the programmed current value.
The STw4102 includes an accurate gas gauge based on a 13-bit AD converter. An external resistor is used between battery and ground to sense a charge/discharge current. With a typical 30 mΩ resistor, current can be up to 2.5 A.

Features
■ Constant current constant voltage (CCCV) linear charger
■ Common or separate USB/wall adapter inputs
■ Fast charge current control up to 1 A for wall adapter and up to 500 mA for USB
■ Support for currents higher than 1 A using external components
■ Programmable charge voltage (4.1 V, 4.2 V, 4.3 V, 4.35 V) with 1% accuracy
■ Thermal regulation
■ Trickle charge mode at low battery voltage
■ Wall adapter voltage up to 16 V
■ Battery overvoltage protection at 4.7 V
■ Gas gauge with 13-bit AD converter
■ Battery voltage monitor with 7-12 bit AD converter
■ I2C interface for device monitoring and control
■ Charge status output pin
■ Power detection output pin
■ Programmable watchdog security timer
■ 4.7 V LDO regulator (with external power MOSFET)

Applications
■ Cellular phones (GSM, CDMA, WCDMA), PDA, MP3 players, cordless phones
■ Digital camera, USB appliances, bluetooth devices, portable navigation devices