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TUSB1042I: EQ settings suggestions

David Gruber
Prodigy 10 points
Part Number: TUSB1042I

We have designed a USB3.0 Type C system and on both devices I used the TUSB1042 multiplexer/re-driver  (https://www.ti.com/lit/ds/symlink/tusb1042i.pdf.  We are talking to the Mux using the I2C connections and there are 3 EQ settings for each device.  We have written some code to sweep through the values but there are 16Mil combinations and performing the sweep on all values will take 635days.  Has anybody used these chips before with success?   What EQ settings worked in your setups?  Is there a good way to pick the values without sweeping through and testing all of them?  Any help would be greatly appreciated.

  • 0
    TI__Guru**** 154861 points

    Hi,

    1. Please make sure the EQ_OVERRIDE bit in register 0x0A is set to 1. This is to make sure the EQ settings based on programmed value of each of the EQ registers.

    2. Register 0x21 EQ compensates the trace insertion loss between the host and the TUSB1042, it is best to verify the EQ setting using a scope running the USB3.0 TX compliance SW.

    3. Register 0x20 EQ compensates the trace length insertion loss between the TUSB1042 and the Type-C connector, it is best to verify the EQ setting using a BERT running the USB3.0 RX JTOL compliance test.

    4. Assuming 10Gbps data rate, we will have roughly 1dB/in loss and we can also assume 1dB loss per via. So for a 6in trace with 2 via, we will have 1dB/in loss * 6in trace + 1dB * 2 via = 8dB. So EQ around 8dB will be a good sweeping point.

    Thanks

    David