Analog Devices AD9866 Instructions Manual page 45

occur during undershoot or overshoot caused by ringing. If the
signal traces cannot be kept shorter than about 1.5 inches,
series termination resistors (33 Ω to 47 Ω) should be placed
close to all digital signal sources. It is a good idea to series-
terminate all clock signals at their source, regardless of trace
length.
The receive RX+ and RX− signals are the most sensitive signals
on the entire board. Careful routing of these signals is essential
for good receive path performance. The RX+ and RX− signals
form a differential pair and should be routed together as a pair.
By keeping the traces adjacent to each other, noise coupled
onto the signals appears as common mode and is largely
rejected by the MxFE receive input. Keeping the driving point
impedance of the receive signal low and placing any low-pass
filtering of the signals close to the MxFE further reduces the
possibility of noise corrupting these signals.
Rev. A | Page 45 of 48
AD9866