Latency in QDR II compared to QDR

Question: Why is there an extra 1/2 clock cycle of latency on the QDR II compared to QDR?

 

Answer:

The QDR II has an internal DLL(Delay Locked loop) which is used to make the TCO(Clock to output time) shorter on the QDR II and hence the extra 1/2 cycle of latency on the initial read. Thus increasing the data valid window.