The JM334D643A-50 is a 32M x 64bits Double Data Rate SDRAM high-density for DDR400.The JM334D643A-50 consists of 8pcs CMOS 32Mx8 bits Double Data Rate SDRAMs in 66 pin TSOP-II 400mil packages and a 2048 bits serial EEPROM on a 184-pin printed circuit board. The JM334D643A-50 is a Dual In-Line Memory Module and is intended for mounting into 184-pin edge connector sockets. Synchronous design allows precise cycle control with the use of system clock. Data I/O transactions are possible on both edges of DQS. Range of operation frequencies, programmable latencies allow the same device to be useful for a variety of high bandwidth, high performance memory system applications.