CCD memory arrays with fast access by on-chip decoding

CCDMEMORY arrays 4096-bit (4k) and 8192-bit (8k) have been developed principally for use in computing systems, and to provide a fast auxiliary memory having average access times in the range 64 to 128 /& at data rates of 1 to 2 MHz. To achieve this, the arrays were organized as recirculating serial memory blocks (tracks) of 256 bits each. The 4k and 8k arrays thus have 16 and 32 tracks, respectively. Random access to any track is provided by on-chip decoding of a 4 or 5-digit address. Data are readout non-destructively, except while the input terminal is enabled, in which case each input data bit replaces the bit which was readout during the previous half clock period