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Does the TS3USB3000 meet USB 3.0 requirements?

Adam Torma
Mastermind 45475 points
Other Parts Discussed in Thread: TS3USB3000, HD3SS6126, HD3SS3212

E2E,

 

Does the TS3USB3000 meet USB 3.0 requirements?

 

Thank you,

Adam

  • 0
    TI__Genius 11665 points

    Hello Adam,

    Thank you for your question.

    This answer is two part. In terms of speed, the TS3USB3000 does meet the USB 3.0 requirement. USB 3.0 requires at least 5 Gbps of speed, and the TS3USB3000 exceeds this spec with a Bandwidth of 6.1 GHz. Please see they eye patterns that verify this spec.

    In terms of configuration, the TS3USB3000 alone will not fulfil the requirements of USB 3.0. USB 3.0 requires two differential muxes, while the TS3USB3000 only offers one differential mux. Therefore, two TS3USB3000 ICs together will give you the proper configuartion for USB 3.0 AND meet the speed requirements for USB 3.0. Please see the picture below with the implementation of USB 3.0 with two TS3USB3000 ICs.

    Regards,

    Jared

  • 0
    Prodigy 20 points
    Hi Jared,

    I am trying to understand the BW parameter here.

    The datasheet mentions the BW to be 6GHz which I understand is the analog BW which means that this switch can pass through a 6GHz SINE wave with amplitude of 0.7x of its Vmax (-3dB).
    USB 3.0 signals are digital square wave signals and are of 5Gbps BW /throughput. Considering this, and a max frequency of roughly about half of this (not considering the encoding), it is 2.5GHz. Considering atleast 5 -7 times of this max frequency (harmonics), the BW of the switch needs to be atleast 10G - 12GHz to be able to reconstruct the square wave properly at the receiver end considering the harmonics to get a better square wave with wider eye and sharp rising edges.

    These are my thoughts and think that 6GHz (3dB) is very close without any margin. We should also consider signal degradation due to PCB layout/routing/external cable/connectors and also the driver's capability. Considering all these possible degrading factors, shouldn't we need higher BW?

    Please let me know what do you think?

    Thanks,
    Nags
  • 0 in reply to Nagalakshmi Rajagopal
    TI__Mastermind 45475 points

    Nags,

    You are correct, the TS3USB3000 datasheet mentions the BW to be 6GHz.  This 6GHz value is the analog BW which means that this switch can pass through a 6GHz SINE wave with amplitude of 0.7x of its Vmax (-3dB).

    You are correct, USB 3.0 signals are digital square wave signals and are of 5Gbps BW /throughput.  

    If you look at our signal switch FAQ page "What is the maximum signal rate or data rate of a signal switch?" you can see that we normally recommend  3 times the fundamental frequency (2.5GHz x 3 = 7.5GHz) for our switch selection.  Our recommendation of selecting a switch with 3 times the fundamental frequency includes sufficient margin.  This margin is clearly demonstrated in the eye diagrams above as the 6Ghz does not significantly degrade the 5Gbps signal.  

    Please keep in mind that for USB3.0 data transmission you would need to use 2x TS3USB3000 ICs devices for both TX and Rx pairs.  If you would like to have an integrated solution I would take a look at parts like HD3SS6126 or HD3SS3212. 

    Thank you,

    Adam