The AP1501 series of regulators are monolithic integrated  circuits that provide all the active functions for a step-down  (buck) switching regulator, capable of driving a 3A load with  excellent line and load regulation. These devices are available  in fixed output voltages of 3.3V, 5V, 12V, and an adjustable  output version.  Requiring a minimum number of external components, these  regulators are simple to use and include internal frequency  compensation, and a fixed-frequency oscillator.  The AP1501 series operates at a switching frequency of 150  kHz thus allowing smaller sized filter components than what  would be needed with lower frequency switching regulators.  Available in a standard 5-lead TO-220 package with several different lead bend options, and a 5-lead TO-263 surface mount package.