Tool/software:
In the previous circuit version, the signal Eye High test failed (as shown in the attached image). Therefore, in this version, we have added the TUSB522P to re-drive the USB signal.
Do you have any recommended settings for the EQ1/2, OS1/2, and DE1/2 of the TUSB522P?
Hello and thanks for reaching out. The EQ, DE and OS settings will depend on the channel loss between the 522P and the USB host/device and connector:
Do you know the loss of the channel before and after the TUSB522P (in dB)? If so, I can help recommend EQ, DE, and OS settings.
Best,
Shane
I am assuming your design uses typical FR4 for the trace material (~0.5dB/in at 5Gbps). This would give the following loss profile:
If you want to place the TUSB522P between the FPC connector and the USB host, I recommend placing it closer to the FPC connector. This allows the re-driver to compensate more of the SSTX channel with EQ. For example, lets say you place the TUSB522P 2cm from the FPC connector:
In this case, you could begin testing with the following settings:
These recommendations rely on assumptions of the board material and re-driver placement, without regard for via count or layout properties. When designing a re-driver in your system its best to add pullup and pulldown options to all EQ/DE/OS settings. This allows you to change the settings as-needed when verifying the board.
Best,
Shane
