SN74ABT18502,pdf(Scan Test Dev

The SN74ABT18502 scan test device with an 18-bit universal bus transceiver is a member of the Texas Instruments SCOPE™ testability IC 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 four-wire test access port (TAP) interface.

In the normal mode, this device is an 18-bit universal bus transceiver that combines D-type latches and D-type flip-flops to allow data flow in transparent, latched, or clocked modes. The device can be used either 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.