Datasheet in PDF format for the SM3509 part, 48.5 KB. The file name gives only the bare part number, so the maker and function must be confirmed from the content. Such sheets supply the pinout, electrical ratings and package information a technician needs to probe the device safely, judge whether measured values are normal and pick a compatible substitute. Open it in any PDF viewer. Since similar SM35xx numbers describe different parts, verify the component marking reads SM3509 before using the data.
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 @datasheet_technar_org. 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.