The HB52E648EN, HB52E649EN belong to 8-byte DIMM (Dual In-line Memory Module) family, and have been developed as an optimized main memory solution for 8-byte processor applications. They are synchronous Dynamic RAM Module, mounted 256-Mbit SDRAMs (HM5225805BTT) sealed in TSOP package, and 1 piece of serial EEPROM (2-kbit EEPROM) for Presence Detect (PD). The HB52E648EN is organized 32M x 64 x 2-bank mounted 16 pieces of 256-Mbit SDRAM. The HB52E649EN is organized 32M x 72 x 2-bank mounted 18 pieces of 256-Mbit SDRAM. An outline of the products is 168-pin socket type package (dual lead out). Therefore, they make high density mounting possible without surface mount technology. They provide common data inputs and outputs. Decoupling capacitors are mounted beside each TSOP on the module board.