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TUSB1002: USB1002AI and TUSB212 schematic review

Pei Gong
Prodigy 510 points
Part Number: TUSB1002
Other Parts Discussed in Thread: TUSB212,

Hi

Below is the application:

PCB trace from USB to HUB2 is about 350MM, 

Could you kindly help to check the direction of schematic, is the USB connect and USB HUB connect to the right pin?

1. Please help to see how to configure (MODE, CFG1, CFG2, CH1_EQ1, CH1_EQ2, CH2_EQ1 and CH2_EQ2 of TUSB1002A.

2. Whether SCL / SDA can float on the design of TUSB212.

In addition, the data sheet of T1002A mentions A to B FR4 Length (inches) and C to D FR4 Length (inches). What is this length related to and what is the demand of length?

  • 0
    TI__Guru 64326 points

    Hi Pei,

    1. The configuration of these pins depends on your application. Please read the TUSB1002A Configuration Guidelines for help selecting your settings for this device. Post any additional question you may have in this thread.
    2. Yes these pins can be left floating if customer only wants to use GPIO. I recommend adding a test point or pull up resistor to allow soldering I2C lines for debug, if needed.
    3. The section of the datasheet you are reffing to is an example of using TUAB1002A where the pre and post channels are at a fixed length. This sections describes how top confrere the device of this application and other similar to it. See FAQ below for additional details. 

    https://e2e.ti.com/support/interface/f/138/t/719929 

    See notes on the schematic below.

    • Recommend C911 and C912 to be 220 nF.
    • Is TUSB1002A connected to the upstream or downstream port of the USB Hub?
    • Does USB1_TX1_P/N connect to the USB Hub RX pins? If not the signals should be switched with USB1_RX1_P/N. 100 nF AC coupling on these lines is good!
    • A TX pin pair should connect to a RX pin pair (input).
    • R1231 and R1230 are not necessary of this design unless there is a passive mux used on the GF_USB1_RX1_P/N) pair.
    • To use TUSB212 in its normal configuration D1P/M must be shorted to D2P/M.
    • TUSB212 should also be used on the USB connector USB 2 lines and the USB 2 Hubs USB 2 lines (DP & DM). 

  • 0 in reply to Malik Barton57
    TI__Prodigy 510 points

    Hi Malik,

    Thanks for your help!

    could you kindly answer another questions?

    1. I selected USB3.2 Dual Channel. Will there be any problem if the speed does not reach the speed of USB3.2? TUSB1002 will work if the power supply is normal?Under what circumstances will the chip not work?


    2. What is the purpose of the capacitors (C909 / C910 / C905 / C906) connected to the RX on the TUSB1002 and the RX corresponding to the HUB? Our general application is to connect capacitors only on the TX.

  • 0 in reply to Pei Gong
    TI__Guru 64326 points

    Hi Pei,

    1. Yes, both Gen 1 and Gen 2 speeds are supported. USB 2 data is handled on a separate bus (DP and DM wires). 

    2. Only AC coupling the TX pin is valid but no longer the recommended practice for external USB ports.The 330 nF AC coupling on RX2 is highly recommend by the USB 3 spec for external USB ports. C905 and C906 should be used to connected the internal USB Host to TUSB1002A. 

  • 0 in reply to Malik Barton57
    TI__Prodigy 510 points

    Hi Malik,

    could you kindly recommend an initial value of VOD and gain settings for TUSB1002A.

    Thanks!

  • 0 in reply to Pei Gong
    TI__Guru 64326 points

    Hi Pei,

    These settings are dependent on the estimated insertion loss of the pre and post channel and layout. Customer will need to tune dependent on testing of the platform. TUSB1002A initial settings could be as follows:

    • EQ Setting #10
    • VOD Setting #11