What is the latency of the DS90CR285 and DS90CR286A?
The DS90CR285 has a latency of 1 clock period plus 5.5 ns max. The DS90CR286A has a latency of 2 clock periods plus 7.5 ns max. Total interconnect latency is Tx Latency + Rx Latency + interconnect flight time. This is slowest at 20MHz (50ns cycle time), being (1x50ns + 5.5ns) + (2x50ns + 7.5ns) + interconnect flight time = 163ns + interconnect flight time. Clearly this will be much less at 66MHz (15.15ns cycle time), being (1×15.15ns + 5.5ns) + (2×15.15ns + 7.5ns) + interconnect flight time = 58.5ns + interconnect flight time.
