The AAT2554 is a fully integrated 500mA battery charger,a 250mA step-down converter, and a 300mA lowdropout (LDO) linear regulator. The input voltage rangeis 4V to 6.5V for the battery charger and 2.7V to 5.5Vfor the step-down converter and linear regulator, making it ideal for applications operating with single-cell lithiumion/polymer batteries.