This part is a kind of semiconductor called LM2578A.

Function of this product has Switching Regulator.

Manufacturers : National Semiconductor

Image and pinout :

Some of the text within the PDF file :

LM1578A/LM2578A/LM3578A Switching Regulator April 1998 LM1578A/LM2578A/LM3578A Switching Regulator General Description The LM1578A is a switching regulator which can easily be set up for such DC-to-DC voltage conversion circuits as the buck, boost, and inverting configurations. The LM1578A features a unique comparator input stage which not only has separate pins for both the inverting and non-inverting inputs, but also provides an internal 1.0V reference to each input, thereby simplifying circuit design and p.c. board layout. The output can switch up to 750 mA and has output pins for its collector and emitter to promote design flexibility. An external current limit terminal may be referenced to either the ground or the Vin terminal, depending upon the application. In addition, the LM1578 [ ... ]

LM2578A PDF Datasheet Download