The STNS01PUR from STMicroelectronics is a Li-ion Linear Battery Charger designed for single-cell lithium-ion batteries. It requires an input voltage of 4.55 - 5.4 V and an input current of 400 µA. This battery charger uses a CC/CV algorithm to charge the battery and allows the fast-charge current to be programmed with an external resistor. It automatically switches to battery power when a valid input voltage is not present and the battery is not empty. This charger includes over-charge, over-discharge, and over-current protection circuitries to prevent the battery from being damaged under fault conditions. It is available in a surface-mount package that measures 3 x 3 x 0.75 mm and is ideal for portable MP3 players, fitness portable devices, and portable low-power applications.