The IDT72275/72285 are exceptionally deep, high speed, CMOS First-In-First-Out (FIFO) memories with clocked read and write controls. These FIFOs offer numerous improvements over previous SuperSync FIFOs, including the following: The limitation of the frequency of one clock input with respect to the other has been removed. The Frequency Select pin (FS) has been removed, thus it is no longer necessary to select which of the two clock inputs, RCLK or WCLK, is running at the higher frequency. The period required by the retransmit operation is now fixed and short.