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I want to use SN54HC244 chips so I started reading the data-sheet. It can be found here or directly here (PDF).

On the first page I don't understand the logic diagram: SN54HC244 logic diagram

1A1, 1A2 and 1A3 output labels are all 1Y1. From the table on the second page and the given the pin numbers (18, 16, 14, 12) I think the labels should be as the following image: SN54HC244 fixed logic diagram

Am I mis-understanding something or is the data-sheet wrong?

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Am I mis-understanding something or is the data-sheet wrong?

Yes, the current version of the datasheet is wrong.

Notice the text "SCLS130E" on the header of most pages in the current datasheet, which tells us that it is revision E. The mistakes which you highlighted were only introduced in the latest revision to that TI datasheet, when it changed from revision D (August 2003) to revision E in May 2016.

Here is the equivalent, correct, diagram from the previous revision D datasheet - see the header text "SCLS130D" below:

logic diagram from Texas Instruments 74HC244 revision D datasheet

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  • \$\begingroup\$ Confirmed by TI: e2e.ti.com/support/applications/hirel/f/935/p/686168/…. They said they will fix this in the next data-sheet version :) \$\endgroup\$ May 3, 2018 at 12:44
  • \$\begingroup\$ @VictorLamoine - Thanks for the update, that's good news :) Well done for finding the mistakes. I wonder how many other people were confused by them, in the 2 years since those mistakes was introduced! \$\endgroup\$
    – SamGibson
    May 3, 2018 at 12:46

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