Please refer to the device datasheet (Intel® Arria® 10 Device Datasheet below) for the Run Length specification.
In addition, the conditions for CDR to shift from LTR -> LTD mode are as follows, and if these conditions are violated, CDR will shift from LTD -> LTR mode.
(Reference) Intel® Arria® 10 Device Datasheet
https://www.intel.com/content/dam/www/programmable/us/en/pdfs/literature/hb/arria-10/ug_arria10_xcvr_phy.pdf
(CDR Lock Modes section)
For Refclk required by CDR, select from the pull-down list.
It depends on the protocol, but basically the input Reference Clock used in the TX PLL is connected and used.
--------------------
Category: Transceivers
Tools:-
Device: Arria® 10