The SN54LS222A 64-bit, low-power Schottky memory is organized as 16 words by 4 bits each. It can be expanded in multiples of 15m + 1 words or 4n bits, or both (where n is the number of packages in the vertical array, and m is the number of packages in the horizontal array); however, some external gating is required. For longer words, the input-ready (IR) signals of the first-rank packages and output-ready (OR) signals of the last-rank packages must be ANDed for proper synchronization. A first-in, first-out (FIFO) memory is a storage device that allows data to be written to and read from its array at independent data rates. These FIFOs are designed to process data at rates up to 10 MHz in a bit-parallel format, word by word.