DDR2 SDRAM is very similar to DDR
SDRAM, but doubles the minimum read or write unit again, to 4 consecutive words. The bus protocol was also simplified to allow higher performance operation. Also, an extra bank address pin (BA2) was added to allow 8 banks on large RAM chips.
Typical DDR2 SDRAM clock rates are 200, 266, 333 or 400 MHz (periods of 5, 3.75, 3 and 2.5 ns), generally described as DDR2-400, DDR2-533, DDR2-667 and DDR2-800 (periods of 2.5, 1.875, 1.5 and 1.25 ns). Corresponding 240-pin DIMMS are known as PC2-3200 through PC2-6400. DDR2 SDRAM is now available at a clock rate of 533 MHz generally described as DDR2-1066 and the corresponding DIMMs are known as PC2-8500 (also named PC2-8600
Xi’an UniIC Semiconductors Co., Ltd.(Xi’an UniIC) was formerly known as Xi’an Sinochip Semiconductors Co., Ltd. which was restructured from Qimonda Technologies (Xi'an) Co., Ltd. in 2009. The company was initially founded in later 2003 as memory product development department of Infineon Technologies (Xi’an) Co., Ltd. After the span off of Qimonda Technologies from Infineon in 2006, it became an own legal entity named Qimonda Technologies (Xi'an) Co., Ltd. 
