TUSB214: Eye diagram issue

Patrick Chen

Part Number: TUSB214
Other Parts Discussed in Thread: TUSB211, TUSB212

Hello

Below is customer topology and they just put TUSB214 on re-driver 2 position close to USB port and re-driver 1 short now. They test EQ level 0~level 3 of TUSB214 but eye diagram still cover the eye mask on below. Has any suggestion to pass eye diagram testing? Thank you.

CPU-->PCIE connector	9 inch
PCIE connector-->re-driver1	2 inch
re-driver1-->re-driver2	10 inch
re-driver2-->USB port	10 inch

EQ Level 3 :

EQ Level 0

Patrick

over 6 years ago

0 WIN Maung over 6 years ago

TI__Expert 3655 points

looks like a lot of DC loss. what dc boost they are using

0 Patrick Chen over 6 years ago in reply to WIN Maung

Mastermind 8875 points

It is recommend to suggest ti tuning DC Boost setting. Could I know the DC boost setting means to add DC bias to 40mV~80mV? What is the situation that need DC boost function? Thank you.

BR
Patrick

0 WIN Maung over 6 years ago in reply to Patrick Chen

TI__Expert 3655 points

Ac boost compensates for capacitive loss and DC boost compensates for resistive loss

They have a lot of resistive loss needs to use higher DC boost.

0 WIN Maung over 6 years ago in reply to WIN Maung

TI__Expert 3655 points

www.ti.com/.../slla392.pdf

0 Patrick Chen over 6 years ago in reply to WIN Maung

Mastermind 8875 points

Hello

Customer use TUSB211 and TUSB214 for the same EQ level 3, but eye diagram looks not different for setting. Is it correct? Thank you.

TUSB214 EQ level 3, DC boost 80mV

TUSB211 EQ level 3

Patrick

0 WIN Maung over 6 years ago in reply to Patrick Chen

TI__Expert 3655 points

TUSB211 EQ 3 is very small, it is the minimum boost setting.

For this system below is my recommendation since I am extracting form what you are telling me that they are not going to use two TUSB214.

They are probably trying below

HOST - TUSB211 - TUSB214

TUSB211 is not the right part since they have a lot of DC loss.

They need to use below

HOST - TUSB212 - TUSB214 and use DC boost one both redrivers.

0 Patrick Chen over 6 years ago in reply to WIN Maung

Mastermind 8875 points

Hello

So TUSB212 is p2p to TUSB211 and TUSB214? So they can use two re-driver TUSB212+TUSB214 to improve DC boost for this case? Thank you.

BR
Patrick

0 WIN Maung over 6 years ago in reply to Patrick Chen

TI__Expert 3655 points

YeS

0 Patrick Chen over 6 years ago in reply to WIN Maung

Mastermind 8875 points

Hello

Customer use TUSB211 and find out another question, If put TUSB211 reset, mother board can access any USB slave device. But put TUSB211 active, some USB device can access but some USB slave device can not access by mother board. What is the issue root cause for it? Thank you.

BR
Patrick

0 Brian Zhou over 6 years ago in reply to Patrick Chen

TI__Guru*** 146165 points

sorry for reply late, when 211 in reset, device is in path though, that's why it's working for any device.
there could be EQ/DC setting issue when device,in active, what is your schematic?

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TUSB214: Eye diagram issue