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TUSB1146: TUSB1146 at source and TUSB1064 and sink

Eric Li3
Prodigy 150 points
Part Number: TUSB1146
Other Parts Discussed in Thread: TUSB1064, , TUSB1064RNQEVM

Hi Madam/Sir,

We were doing feasibility study for putting  TUSB1146 at source, TUSB1064 at sink and connecting both thru a USB type C cable.

It expected to transmit up to 720P video over it and we wondered to learn "what is the max acceptable return loss and insertion loss contributed by the USB type C cable and connectors"?

Thanks for your support.

Regards,

Eric Li

  • 0
    TI__Guru**** 156171 points

    Eric

    Does my answer in this e2e thread, e2e.ti.com/.../tida-01620-for-display-port-over-usb-c-is-there-any-way-to-make-the-usb-c-cable-length-up-to-10-meter provide an adequate response or are you looking for additional data?

    Thanks

    David

  • 0 in reply to David (ASIC) Liu
    Prodigy 150 points

    Hi David,

    Thanks for your support. Your answer resolved my question.

    We have an additional question that we wondered "what is the channel specification of the USB3.2 between TUSB1146 and TUSB1064? includes SDD11, differential return loss, SDD21, differential insertion loss and intra-skew. With these information, we can make adequate USB type C cable for our application.

    here is the channel specification of FPD-LINK III, for your reference.

    Regards,

    Eric Li

  • 0 in reply to Eric Li3
    TI__Guru**** 156171 points

    Eric

    They are in the datasheet, below is an example from the TUSB1146 datasheet.

    Thanks

    David

  • 0 in reply to David (ASIC) Liu
    Prodigy 150 points

    Hi David,

    Thanks for your support.

    I am not quite understand the Figures mean.

    For the worst case of insertion loss, return loss and intra-skew, can you please share us in simple words? Just like what TI replied for FPD-LINK III above.

    i. SDD11, differential return loss, is around XX dB

    ii. SDD21, differential insertion loss, is around YY dB

    iii. intra-skew, should be less than ZZ ps

    Regards,

    Eric Li

  • 0 in reply to Eric Li3
    TI__Guru**** 156171 points

    Eric

    For the SD11, please refer to the below figure for the input and output return loss. For example, at 1GHz (red line), it will give you the dB for each lane.

    For SDD21, insertion loss, it is impacted by the EQ Gain as shown below. 

    Intra-pair routing (between P and N) should be kept to less than 5 mils.

    Thanks

    David

  • 0 in reply to David (ASIC) Liu
    Prodigy 150 points

    Hi David,

    Thanks for your support.

    for intra-pair, we will keep <5mil of difference between P and N.

    for intra-pair skew, can you give us the worst case in pico second? for 100 ps.

    furthermore, for USB operation speed, 480Mbps, 5 Gbps, 10 Gbps or others, how the host determine it?

    Regards,

    Eric Li

  • 0 in reply to Eric Li3
    TI__Guru**** 156171 points

    Eric

    USB2 and USB3 are two separate buses.

    For USB2, device connection is detected by the 1.5k pullup on DP inside the device. Once the connection has been established, a device that is high speed capable, upon receiving a USB RESET (both D+ and D− driven LOW by host for 10 to 20 ms), it pulls the D− line high, known as chirp K. This indicates to the host that the device is high bandwidth. If the host/hub is also HS capable, it chirps (returns alternating J and K states on D− and D+ lines) letting the device know that the hub operates at high bandwidth. The device has to receive at least three sets of KJ chirps before it changes to high speed terminations and begins high speed signaling.

    For USB3, device connection is detected by both the host and the sink using RX.DETECT. It then uses the low frequency periodic signal (LFPS) that was introduced in USB 3.0 and it changes it slightly to turn into a pulse width modulation message, called the LFPS-Based PWM Messaging (LBPM).

    The LBPM works by the transmitter driving its LFPS for about a quarter of a period to say that this is a "logic 0." It drives its LFPS for about three quarters of the period to say that it is a "logic 1." With this zero/one encoding, the transmitter and receiver can actually talk to each other before the link has even trained to either the 5 Gbps or the 10 Gbps rate. Below shows LBPM definition.

    Thanks

    David

  • +1 in reply to David (ASIC) Liu
    Prodigy 150 points

    Hi David,

    Thanks for your support.

    We got TUSB1146EVM and TUSB1064RNQEVM and will give it a try.

    To learn about the max length of USB type C cable when it transmit a 720P video.

    Regards

    Eric Li