The HB52RF648DC, HB52RD648DC are a 32M x 64 x 2 banks Synchronous Dynamic RAM Small Outline Dual In-line Memory Module (S.O.DIMM), mounted 16 pieces of 256-Mbit SDRAM (HM5225805BTB) sealed in TCP package and 1 piece of serial EEPROM (2-kbit) for Presence Detect (PD). An outline of the products is 144-pin Zig Zag Dual tabs socket type compact and thin package. Therefore, they make high density mounting possible without surface mount technology. They provide common data inputs and outputs. Decoupling capacitors are mounted beside TCP on the module board. Note: Do not push the cover or drop the modules in order to protect from mechanical defects, which would be electrical defects.