TUSB1064: USB3.0 interference DP lead OLED flash when TUSB1064 use as 2 lane DP and 2 lane USB3.0

steven young

Part Number: TUSB1064

Hi TI,

Our produc is VR device that use tusb1064 as MUX;2lane DP run 8.1Gbps transmit 3840*1920@60Hz image,2lane USB 3.0(gen1)transmit camera UVC.when we connect our device to computer,OLED of our device start to flah badly,TUSB1064 setting DP EQ =10dB USB3.0=10dB if we adjust less USB 3.0EQ to 0.7dB,flash of OLED can lighten,if we remove USB3.0 connect in hardware ,OLED will not flash;

Why USB3.0 interference DP?How to fix it? thanks!

over 4 years ago

0 David (ASIC) Liu over 4 years ago

TI__Guru**** 176371 points

Hi,

Can I take a look at your schematic and layout? Do you see any possible source of crosstalk between the USB and DP on the board?

Thanks

David

0 steven young over 4 years ago in reply to David (ASIC) Liu

Prodigy 60 points

tusb1064_shcematic&pcb.rarHi David,

Left leg of glass consist of three part attached is schematic&pcb,please review it.

0 steven young over 4 years ago in reply to steven young

Prodigy 60 points

tusb1064_shcematic&pcb.rarHi David,

Left leg of glass consist of three part attached is schematic&pcb,please review it.

0 David (ASIC) Liu over 4 years ago in reply to steven young

TI__Guru**** 176371 points

Hi,

Looking at the diagram, is the cable between GLASS_LEFT_SUB_USB_part1 and GLASS_LEFT_SUB_MID_1064_part2 twisted and individually shielded? Have you done any crosstalk measurement on the cable?

Looking at the GLASS_LEFT_SUB_MID_1064_part2 layout, my concern is on the ground guard trace being placed between the DP and USB signal.

1. I don't see the ground guard trace being terminated end to end

2. I don't see shorting via being spaced evenly on the ground guard trace.

For more information on ground guard trace, please refer to this link: https://blog.lamsimenterprises.com/2013/04/12/are-guard-traces-worth-it/

Thanks

David

0 steven young over 4 years ago in reply to David (ASIC) Liu

Prodigy 60 points

Hi David,

The cable is coaxial ,there is well ground shielded;because of considering cost ,we use through via,cannot take way of shorting via ，distance is more 3 line width between DP and USB3.0 ，crosstalk should not happen;we will measure NEXT and FEXT,see what is happened.

0 David (ASIC) Liu over 4 years ago in reply to steven young

TI__Guru**** 176371 points

Hi,

Thanks for the update. I agree with you that we need to measure both the NEXT and FEXT.

David

Interface

Interface forum

TUSB1064: USB3.0 interference DP lead OLED flash when TUSB1064 use as 2 lane DP and 2 lane USB3.0