I found that the eye diagram read by Rx is relatively small.
The eye width is 0.375ui and the eye height is 250mv.
So what parameters should I adjust to make the eye diagram better? Thank you!
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I found that the eye diagram read by Rx is relatively small.
The eye width is 0.375ui and the eye height is 250mv.
So what parameters should I adjust to make the eye diagram better? Thank you!
Hi,
These eye opening values meet TI recommended minimum thresholds for error free operation. But I think we can improve them.
Have you tried using DFE enabled with adapt mode 2? See below.
Table. Adapt mode 2, Enable the DFE
STEP |
SHARED/ CHANNEL REGISTER SET |
OPERATION |
REGISTER ADDRESS [HEX] |
REGISTER VALUE [HEX] |
WRITE MASK [HEX] |
COMMENT |
1 |
Channel |
Write |
31 |
40 |
60 |
Adapt Mode = 2 |
2 |
Channel |
Write |
23 |
40 |
40 |
Enable DFE Override |
3 |
Channel |
Write |
1E |
02 |
0A |
Enable DFE (DFE_PD=0) and enable DFE taps 3-5 (EN_PARTIAL_DFE=1) |
Note: A CDR reset and release operation is recommended after applying above settings
Cordially,
Rodrigo Natal
HSSC Applications Engineer
Yes, I tried to adjust these parameters, but the eye diagram parameters did not improve
Hi,
Try enabling the CTLE limiting output mode, by setting channel register 0x13[2]=1. In addition ensure that EQ_HI_GAIN is enabled i.e. 0x13[5] is set to 1.
Regards,
Rodrigo Natal