The HD74AC670 contains 16 high speed, low power, transparent D-type latches arranged as four words of four bits each, to function as a 4 x 4 register file. Separate read and write inputs, both address and enable, allow simultaneous read and write operation. The 3-state outputs make it possible to connect up to 128 outputs to increase the word capacity up to 512 words. Any number of these devices can be operated in parallel to generate an n-bit length.