Named only SDLS189, this 667 KB PDF is a datasheet with no part number given in the title. The SDLS prefix follows Texas Instruments literature numbering for logic family datasheets, so the content is probably a TTL or similar logic device, which the front page will confirm. Typical sections cover package options, function tables, switching characteristics and supply limits. Reading them lets you verify correct supply voltage at the VCC pin and expected output states while troubleshooting digital circuitry on a board.
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