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TUSB1021-Q1: schematic review

user5883945
Expert 2096 points
Part Number: TUSB1021-Q1
Other Parts Discussed in Thread: TUSB1142,

Dears,

Due to temperature considerations, we replaced your TUSB1142 (debugged and passed) with the TUSB1021. The routing is similar, but the TUSB1021 consistently fails to detect USB 3.0 at the backend. Please review the schematic and provide any debugging suggestions if possible. The project is urgent, so we kindly request a prompt response.

TE1000-CN-TYPE-C-YL(1).pdf 

  • 0
    TI__Mastermind 47621 points

    Hi,

    This is odd. Can you share the EQ settings used for the TUSB1142 in the past, and the current EQ settings for the TUSB1021-Q1?

    Please provide me with 1-2 business days to complete the schematic review.

  • 0 in reply to Vishesh Pithadiya
    Expert 2096 points

    Hi,

    Two issues with TUSB1142:

    1. Change CEQ1/CEQ0 status from 00 to FF
    2. CRX capacitors, changed from 220nf to 330nf (0201 package).
    Can read USB 3.0


    TUSB1021 Question

    1. Changing EQ1 and EQ0 from 11 to FF and 00 has no effect;
    Problem

    2. SSEQ1 and SSEQ0 are in states 11 and 00, and USB 2.0 cannot communicate; The status has been changed to FF, and USB 2.0 is functioning normally; But USB 3.0 still cannot be used.
    3. RX capacitor, changing the original 330nf to 220nf, USB 3.0 still cannot be used.
    Now adjusting any parameters (the power supply is 3.3V, the same as TUSB1142), USB 3.0 cannot be used.

  • 0 in reply to user5883945
    TI__Mastermind 47621 points

    Hi,

    Here is the schematic review.

    TUSB1021Q1_Schematic_Review_TE1000(12_9_2025).pdf

    I see that the EQ can either be set at 00 or 11. 00 is most likely under equalizing signal, and 11 is likely overcompensating the signal. 

    When using EQ tuning you need all the options the redriver has available. Please install PUP and PDOWN resistors for the control signals.

    We also need to understand what losses we plan to compensate for. 

    Can you share the loss in dB of the pre-channel (Between TUSB1021-Q1 and host) and post-channel (Between TUSB1021-Q1 and connector)?

    You can use the approximation of 1dB/inch for 10Gbps signaling. This is how we will determine the appropriate EQ required.

    The TUSB1142 has an adaptive eq feature which enables the part to automatically do this tuning, but the TUSB1021-Q1 does not have this feature.