The 'LVTH18512 and 'LVTH182512 scan test devices with 18-bit universal bus transceivers are members of the Texas Instruments SCOPE TM testability integrated-circuit family. This family of devices supports IEEE Std 1149.1-1990 boundary scan to facilitate testing of complex circuit-board assemblies. Scan access to the test circuitry is accomplished via the 4-wire test access port (TAP) interface. Additionally, these devices are designed specifically for low-voltage (3.3-V) VCC operation, but with the capability to provide a TTL interface to a 5-V system environment. 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. SCOPE, Widebus, and UBT are trademarks of Texas Instruments Incorporated. Copyright 1997, Texas Instruments Incorporated