Datasheet for the STA350BW, distributed as a 2.11 MB PDF. The file name gives only the part number, so the document itself is the reference for the pinout, package drawing, electrical characteristics and recommended application circuit. When repairing a board carrying this chip, the datasheet helps you identify supply and output pins, compare measured voltages with specified values and judge whether the part has failed. Check that the marking on the package matches the part number before relying on any pin assignments.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @datasheets0. Enginerys does not host this file.
How to open a .pdf file
The standard format for schematics, block diagrams, power-sequence charts and service manuals.