SDLS206 labels this 468 KB PDF datasheet, with no part number given in the name. The prefix is the style Texas Instruments uses for logic literature, so the document probably describes a logic IC, but read its title to be sure. Repair technicians use such sheets to check pinouts and function tables while tracing signals, and to compare supply range and output drive when selecting a substitute. Open it with any PDF reader and match the device marking on the board.
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.