HD3SS213ZQER DP 1 to 2 and 1 to 4 port DP product can not work at 4K2K resolution.

Hello,

The schematic looks fine, it might be a layout issue, could you share the brd file?
Regards,
Diego.

Dear Diego:

First, thank you so much for your reply.

Attached file is 1 to 4 and 1 to 2 DP board PCB gerber.

I have checked the layout taht I think the input trace of DP LAN is too long.

Do you have any comment and give me some suggestions?

Thank you so much.

Lucas

Gerber.rar.

Dear Diego:

I have provided HD3SS213 1 to 2 and 1 to 4 PCB layout on 11/18.
Do you have any comment for PCB layout?
Please give me some suggestion for layout.
Thank you so much.

Hello Lucas,

I am sorry for the delay, but I am unable to open the gerber files, could you share a PCB file compatible with Cadence?

Regards,
Diego.

Dear Diego:

I got Cadence format PCB files.

Please check attached file.

I have checked the PCB layout and just think input trace is too long to effect output port at 4K 2K resolution.

I have no any idea that only apply TI SN75DP126 re-driver EVM to solve customer's issue .  

Thank you so much.

Lucas 2015/12/01

PCB.rar

Dear Diego:

I got your suggestion.

I will beg customer to modify PCB layout for output channel differential pair.

I think this need time to do layout modifacation.

And I will report the result to you know and close this case.

Thank you so much again.

Lucas 2015/12/02

Dear Diego:

I discussed the same trace length of TX and RX pairs with my customer.

We have two questions need to your answers.

1. The same trace length is meaning that all of DP TX & RX pair for output port or for DP input port.

2. For DP output port (1 output port have 4 LAN differential pairs), that meaning is all of 4 LAN output port trace need to lay the same length.

Please give us some comment.

Thank you so much.

Lucas 2015/12/04

Dear Diego:

Thanks for your information.
I will beg my customer to modify PCB layout for different pair.
Thank you again.

Lucas.

Dear Diego:

My customer followed your suggestion to modify 1 to 2 DP port PCB layout and provided trace length data, PCB layout file and PCB drawing to check.

I have cheked the layout and I think that is ok, maybe.

Please check these files.

Thank you.

LucasAP-202-DP-R022_pads.brdAP-202AU-DP-R022-100ohm.pdfap-202-r022.pdf

Hi Lucas,

This version of PCB has a better length matching than previous version, however I see you removed the diff-pair constrains, please add them again to make sure you are meeting differential impedance. Besides, you can add constrains to have a better length matching.

Displayport defines inter-pair and intra-pair skews in time, not length, however we recommend having intra-pair mismatch no more than 5mils and inter-pair skew no more than 20mils. On A port side, bumps to match length could be placed in a better way.

If this layout improvements doesn't solve the problem you may think about placing a redriver like SN75DP130.
If you can get eye diagramas, it would show where is the problem is.

Regards