The L4975A is a stepdown monolithic power switching regulator delivering 5A at a voltage vari- able from 5.1 to 40V. Realized with BCD mixed technology, the device uses a DMOS output transistor to obtain very high efficiency and very fast switching times. Features of the L4975A include reset and power fail for mi- croprocessors, feed forward line regulation, soft start, limiting current and thermal protection. The device is mounted in a 15-lead multiwatt plastic power package and requires few external compo- nents. Efficient operation at switching frequencies up to 500KHz allows reduction in the size and cost of external filter components.