TUSB522P: USB3.0 redriver question list

Hi Yishan,

Yishan Chen said:

The EQ/DE effect for long USB3.0 signal transmission (Application curve(eye-diagram) in near-end and far-end)

The diagrams we have taken in the datasheet are near end waveforms. 

Yishan Chen said:

How to get the proper EQ/DE configuration based on the application usage

To do this we must understand/ approximate the loss associated with the system. There are two loss profiles we must understand. pre-channel (from SoC to redriver), and post-channel (from redriver to USB connector). The primary function of the redriver is equalization (digital bandpass filter) this will boost the higher frequency components of the signal to match the loss associated with the trace/cable. The TUSB522p has 3 options 3dB, 6dB, and 9dB. After using the proper equalization we may need an improvemnt to the eye. This is where OS and DE settings come in. the OS settings increase the output swing (Vpp) of the redriver for longer channel operations. 

De operates as follows.

DE allows for the transitions bits (highest frequency components of the signal here) to be boosted, so the higher loss at the higher frequency can be compensated for. 

Yishan Chen said:

What is the possible risk if the EQ/DE/OS parameter mismatch

This could lead to an under-equalized or over-equalized signal. This could result in an failing eye diagram or jitter test.

Yishan Chen said:

What could ‘swing’ done in the system

The swing is the Vpp of the USB signal. Having a higher swing means that the signal will have a higher tolerance for insertion loss because of the larger voltage of the swing.

Yishan Chen said:

What is the best place to place the redriver

Its best to place the redriver as follows:

Redriver Placement Training.pptx

let me know if you have nay questions!