PDF datasheet, 570 KB, whose name SDLS187 is just a document code rather than a part name. Codes with the SDLS prefix belong to the literature system Texas Instruments uses for standard logic datasheets, so open it to see which device and package variants it covers. Logic datasheets give connection diagrams, timing waveforms and voltage thresholds. These figures let a technician decide whether a marginal signal is valid high or low and whether a substitute family part will work in the same socket.
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.