The R5651 Series from Nisshinbo Micro Devices is an Overcharge and Discharge Protection IC for 3 to 5-series cell Li-ion / Li-polymer rechargeable battery pack. This IC requires an input voltage of 4 V - 25 V. It can select any number of cells by applying a certain voltage on the SEL pin. This IC uses a current-sense resistor with low resistance ratings that help reduce the high temperature of large currents and achieve the thermal design of a board easily. It has a separation between charging and discharging paths to achieve low impedance of the battery pack. This IC employs the cascading technique to achieve simple circuit configuration for battery packs with six cells or more, as well as to reduce external components. It includes short-circuit and protection circuits for charge and discharges overcurrents. This IC is available in a through-hole package that measures 7.8 x 6.4 mm.