SN54LS638, SN54LS639, SN74LS638, SN74LS639 OCTAL BUS TRANSCEIVERS SDLS188 – JANUARY 1981 – REVISED MARCH 1988 Copyright 1988, Texas Instruments Incorporated PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 1 SN54LS638, SN54LS639, SN74LS638, SN74LS639 OCTAL BUS TRANSCEIVERS SDLS188 – JANUARY 1981 – REVISED MARCH 1988 2 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 SN54LS638, SN54LS639, SN74LS638, SN74LS639 OCTAL BUS TRANSCEIVERS SDLS188 – JANUARY 1981 – REVISED MARCH 1988 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 3 SN54LS638, SN54LS639, SN74LS638, SN74LS639 OCTAL BUS TRANSCEIVERS SDLS188 – JANUARY 1981 – REVISED MARCH 1988 4 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265