DDR3 and DDR2

The difference between DDR3 and DDR2 on Timing:

Timing: Just like the number of delay cycles after the DDR2 transition from DDR, the DDR3 CL cycle will also be higher than DDR2.

The CL range of DDR2 is generally between 2 and 5, while DDR3 is between 5 and 11, and the design of the additional delay (AL) is also changed.

The range of AL is 0~4 for DDR2, while AL has three options for DDR3, namely 0, CL-1, and CL-2. In addition, DDR3 also adds a new timing parameter - Write Delay (CWD). This parameter will be based on the specific operating frequency.