The the EDD5108AD and the EDD5116AD are 512M bits Double Data Rate (DDR) SDRAM. Read and write operations are performed at the cross points of the CK and the /CK. This high-speed data transfer is realized by the 2 bits prefetch-pipelined architecture. Data strobe (DQS) both for read and write are available for high speed and reliable data bus design. By setting extended mode register, the on-chip Delay Locked Loop (DLL) can be set enable or disable.