DS250DF410: DS250DF410

Hi,

Did you try enabling the DS250DF410 PRBS checker to confirm that errors are occurring at the retimer input? You should do this to isolate whether the link segment with issue is "Switch Tx to Retimer Rx" or "Retimer Tx to Switch Rx"

Your reported HEO > 0.5UI and VEO > 360mV values both meet and exceed TI's recommended minimum thresholds for error free operation. The retimer eye opening values are however for high probability BER of 1E-6. If errors are indeed being observed by retimer PRBS checker, then we would be dealing with low probability jitter, either random jitter or bounded uncorrelated jitter from crosstalk. One thing you may try in such case is increasing the retimer CDR bandwidth by increasing the CDR charge pumps. A higher CDR bandwidth allows it to better track the input jitter. The default value for the DS250DF410 CDR charge pumps is 5. You may increase it to 9 or 10 and see if the long duration test bit errors go away.

Table 1. Adjust CDR Bandwidth

Table 2. Adjust CDR Bandwidth (continued)

Cordially,

Rodrigo Natal

HSSC Applications Engineer