DS250DF810: DS250DF810 RX eye diagram problem

user4838693

Prodigy 190 points

Part Number: DS250DF810

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!

over 3 years ago

0 Rodrigo Natal over 3 years ago

TI__Mastermind 19225 points

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

0 user4838693 over 3 years ago in reply to Rodrigo Natal

Prodigy 190 points

Yes, I tried to adjust these parameters, but the eye diagram parameters did not improve

0 Rodrigo Natal over 3 years ago in reply to user4838693

TI__Mastermind 19225 points

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

Interface

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DS250DF810: DS250DF810 RX eye diagram problem