The ’LVTH18502A and ’LVTH182502A scan test devices with 18-bit universal bus transceivers are members of the Texas Instruments SCOPE™ testability integrated-circuit family. This family of devices supports IEEE Standard 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) VCCoperation, but with the capability to provide a TTL interface to a 5-V system environment.

In the normal mode, these devices are 18-bit universal bus transceivers, that combine with D-type latches and D-type flip-flops, they allow data to flow in the transparent, latched, or clocked modes. Another use is as two 9-bit transceivers or one 18-bit transceiver. The test circuitry can be activated by the TAP to take snapshot samples of the data appearing at the device pins or to perform a self test on the boundary-test cells. Activating the TAP in the normal mode does not affect the functional operation of the SCOPE universal bus transceivers.Read more