The L4973 is a step down monolithic power switching regulator delivering 3.5A at fixed voltages of 3.3V or 5.1V and using a simple external divider output adjustable voltage up to 50V. Realized in BCD mixed technology, the device uses an internal power D-MOS transistor (with a typical RDS(on) of 0.15) to obtain very high efficiency and very fast switching times. Switching frequency up to 300KHz are achievable (the maximum power dissipation of the packages must be observed).