These bus buffers feature three-state outputs that, when enabled, have the low impedance characteristics of a TTL output with additional drive capability at high logic levels to permit driving heavily loaded bus lines without externalpullup resistors. When disabled, both output transistors are turned off, presenting ahigh-impedance state to the bus so the output will act neither as a significant load nor as a driver. The'125 and 'LS125A devices' outputs are disabled when G is high. The '126 and 'LS126A devices'outputs are disabled when G is low. The SN54125, SN54126, SN74125, SN74126, and SN54LS126A are obsolete and are no longer supplied. Copyright (C) 2002, 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. Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.