| Description & Applications | Lithium-Ion Battery Charge Controller The LM3420 series of controllers are monolithic integrated circuits designed for charging and end-of-charge control for Lithium-Ion rechargeable batteries. The LM3420 is available in five fixed voltage versions for one through four cell charger applications. Included in a very small package is an (internally compensated) op amp, a bandgap reference, an NPN output transistor, and voltage setting resistors. Applications： n Lithium-Ion battery charging n Suitable for linear and switching regulator charger |