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DS280BR820: DS280BR820

Gang Liu
Prodigy 130 points

Part Number: DS280BR820

Hi,

I have a question about 25G re-driver, DS280BR820.

If I drop the link speed to like 10GKR, can this re-driver still support? I suppose it should be speed(less than 25G) and protocol transparent or independent, is that true?

Thanks.

  • 0
    TI__Mastermind 41143 points

    Hi Gang,

    Yes, it would support a link speed drop to 10G-KR since this behaves as a linear (transparent) device.  Please note that due to the CTLE curve, this device would provide less boost to signals at 10G than it would at 25G.

    Thanks,
    Drew

  • 0 in reply to Drew Miller1
    Prodigy 130 points

    Thanks for the reply.

    10GKR can be supported, noted.

    If we have one EQ setting for 25G, like 10dB boost; when we drop to 10G, the same one setting will be like 5dB boost? Is that true? 

  • 0 in reply to Gang Liu
    TI__Mastermind 41143 points

    Hi Gang,

    I've granted you access to the DS280BR820 design resources folder.  You'll find the programming guide in this folder.  Table 24 in the programming guide has information about DS280BR820 CTLE boost at different frequencies.

    In general, your thought process can be used as an estimate, although I would recommend referencing empirical data as possible.  For example, one CTLE setting provides 11.1 dB of boost at 12.9 GHz and 4.2 dB of boost at 5.2 GHz. 

    12.9 Ghz / 5.2 GHz = 2.5

    11.1 dB / 2.5 = 4.4 dB

    Thanks,

    Drew

  • 0 in reply to Drew Miller1
    Prodigy 130 points

    Hi Drew,

    (1) Can you please point me the location of the resources folder? Thanks.

    (2) 11.1 dB of boost at 12.9 GHz and 4.2 dB of boost at 5.2 GHz, this part I am clear, not sure what is below equations:

    12.9 Ghz / 5.2 GHz = 2.5

    11.1 dB / 2.5 = 4.4 dB

  • 0 in reply to Drew Miller1
    Prodigy 130 points

    I just saw the email notice of the folder, (1) is clear.

  • 0 in reply to Gang Liu
    TI__Mastermind 41143 points

    Hi Gang,

    Gang Liu said:

    (2) 11.1 dB of boost at 12.9 GHz and 4.2 dB of boost at 5.2 GHz, this part I am clear, not sure what is below equations:

    12.9 Ghz / 5.2 GHz = 2.5

    11.1 dB / 2.5 = 4.4 dB

    You had asked if we have one EQ setting for 25G, like 10dB boost; when we drop to 10G, would the same one setting have around 5dB boost.  I think your general question is if boost has a linear relationship with frequency.  For example, 25G is roughly 2x frequency of 10G.  Because of this, do we expect 10G to have 1/2 boost of 25G.

    I was trying to add onto this with the equations and information from the programming guide.  12.9 GHz is about the nyquist frequency for 25G data, and 5.2 GHz is about the nyquist frequency for 10G data.  If we assume there is a linear relationship between boost and frequency, then boost at 5.2 GHz should be about 1/2.5 the boost at 12.9 GHz.

    In general, I would recommend using data from the programming guide on the boost of this device.  The equations were just an example to demonstrate a roughly linear relationship between boost and frequency between 5.2 GHz and 12.9 GHz.

    Thanks,

    Drew