Data Valid Time (tDV) is indicated as 12ns minimum (refer to Table 25 On page
31 of the AD9959 RevB data-sheet. This can't be true with respect to the fast
5ns serial-data clock? Should it be 1.2ns instead?
12nS is correct. This timing is for a read operation (Figure 42). Read
operations were not designed for speed like the write operation. 12ns is what
the designers targeted as the minimum.