The Texas Instruments SN74CBT16212CDL is a 12-bit Bus FET Exchange Switch from the 74CBT series. It routes and swaps 12-bit-wide data buses using a 12 x 2:2 switching topology — each of the 12 bits has two independent 2:2 exchange paths, letting you cross-connect or swap signal pairs without external mux logic. This is a niche logic function for board-level bus reordering, byte-swapping, or redundant-path switching in 5V systems.
Housed in a 56-BSSOP (0.295-inch, 7.50 mm wide) body, also called 56-SSOP. The fine pitch (0.65 mm typical) and narrow body mean it is not a hand-solder-friendly part for most techs — you will want a stencil, a proper reflow profile, and a microscope for inspection.