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TUSB2E221: eUSB2.0 Host Data Eye Test fail due to EOP Width

Logan
Prodigy 130 points

Part Number: TUSB2E221

Hi Ti team

We currently design the eUSB2.0 interface of the NVL platform, which is connected to the USB TYPE-A port of the motherboard via the single port repeater TUSB2E2211005VBW. However, the high-speed eye diagram quality test for USB2.0 has failed, due to the EOP width test results being 10.4/10.5/10.6.

We have consulted the USB-IF SPEC eUSB2.0 V1.2 and found that the EOP of eUSB is several UI more than USB at low-speed and full-speed, but it is the same as USB2.0 at high-speed, which is 8UI.Under high-speed condition, the common testing standard is 7.5~8.5ui.

Could you please help confirm if this information is accurate? If it is accurate, how should we adjust the TUSB2E221 regarding EOP fail.

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  • 0
    TI__Guru 62005 points

    Hello,

    Using an eUSB2 repeater in an eUSB2 connection will result in an increased EOP width, as this is introduced in the conversion from eUSB2 to USB2 signaling. This change in width, however, is expected when using a repeater.

    The USB-IF's official USB2 Signal Analysis tool takes this increase width into account when performing testing, so if you are not using that tool for testing, I would recommend trying that: www.usb.org/.../usbet20

    Make sure you are using the eUSB2 Repeater section of the tool when performing testing.

    Thanks,

    Ryan