Hi. Referring to the XIO2001 datasheet. The section 8.3.2.3 Ref Clock did not mentioned the length match requirement between REFCLK+ & REFCLK-.
What is the trace length differences allow for REFCLK+/-?
For example: The TX/RX +/- data got mentioned the 5 mils differences.
The differential signal trace lengths associated with a PCI Express high-speed link must be length matched
to minimize signal jitter. This length matching requirement applies only to the P and N signals within a
differential pair. The transmitter differential pair does not need to be length matched to the receiver
differential pair. The absolute maximum trace length difference between the TXP signal and TXN signal must
be less than 5 mils. This also applies to the RXP and RXN signal pair.
4. If a differential signal pair is broken into segments by vias, series capacitors, or connectors, the length of the
positive signal trace must be length matched to the negative signal trace for each segment. Trace length
differences over all segments are additive and must be less than 5 mils.
Thanks,
Chun Ling Chen
