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TUSB217A: Boost and pre-equalization funtion

Chau Nguyen
Prodigy 245 points
Part Number: TUSB217A
Other Parts Discussed in Thread: TUSB217,

Hi Team,
I have two questions about TUSB217
Question 1:
I know to compensate ISI jitter, we can use equalization at the receiver, and pre-emphasis and de-emphasis at the transmitter. In TUSB217 use the pre-equalization, pre-equalization is equalization at the receiver or pre-emphasis at the transmitter? What is this?
Question 2:
What difference is between boost function (edge booster) and pre-equalization about function, ac response, eye diagram affection? I read the Application Cures part, but I can’t clearly understand the difference and function between boost function and pre-equalization function.
Thanks,

  • 0
    TI__Guru 60865 points

    Hello Chau,

    1. RX_SEN  compensates ISI jitter.  It impacts the eye distribution.

    2. BOOST is both AC BOOST (edge boost) and DC BOOST (level boost) combined and impacts eye width / height.

    Regards,

    JMMN

  • 0 in reply to JMMN
    Prodigy 245 points

    Hi JMMN,

    Thanks you very much, 

    I got it, but I'm concerned about the effect BOOST and RX_SEN in each setting application Cures part.

    Can you share me about current injector in DC BOOST and AC BOOST and gain of equalization RX_SEN in each setting level.

    Thanks,

    Chau 

  • +1 in reply to Chau Nguyen
    TI__Guru 60865 points

    Hi Chau,

    The impact of the BOOST level will vary significantly based on the application, the curves in the datasheet are typical values.

    Due to the nature of our USB 2 redriver solution there is no specific insertion loss (in dB) that accurately corresponds to a particular boost setting of the device. Please find the rough estimates below for AC boost provided by TUSB217A. These numbers are based on eye diagrams in the datasheet and are all typical values.

    AC Boost at 240MHz (typ)
    Boost 0: 3.0 dB
    Boost 1: 3.5 dB
    Boost 2: 4.7 dB
    Boost 3: 5.2 dB

    Regards,

    JMMN

  • 0 in reply to JMMN
    Prodigy 245 points

    Hi JMMN,

    Thanks you for your information!