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DS100KR800 Recommendation

David Escandon
Expert 2175 points
Other Parts Discussed in Thread: SN65LVCP1414, SN65LVCP1412, DS100KR800, SN65LVCP114

TI Team,

It's not clear from the datasheet if I can use this redriver device on 10G SFI signals. I would appreciate your input on the following:

I intend to use this repeater on the 10G SFI (for SFP+) signals between two IC with a midplane.

IC --- (10 inches FR4) àconnector – (3 inches FR4) --connector à repeater --- (10 inches FR4)à IC

I am wondering if I should put another repeater before midplane make it like this.

IC --- (10 inches FR4) àrepeater à connector--- (3 inches FR4) --connector à repeater --- (10 inches FR4)à IC

Questions:
Will this part work for SFI signals?
Do we need 2 repeaters, one before midplane and one after?

  • 0
    TI__Mastermind 20820 points

    Hi David, 

    Whether you are going to need the extra repeater/equalizer or not is going to depend on the attenuation of your channel. You should take a look at the SN65LVCP1414 and SN65LVCP1412,  they are two of our newer parts that except SFI signal and work up to 14.2Gbps.They are linear equalizers that preserve the shape of the original signal by compensating for losses in your channel.

    Regards,

    Mike

  • 0 in reply to Michael Peffers
    Expert 2175 points

    Thank you Mike.

    Here are two more questions I'd like your opinion on:

    1. What is the difference between DS100KR800 and SN65LVCP1414. The datasheet indicates that they both have equalizers, but DS100KR800 has de-emphasis, which should make it better, right? Do I understand this correctly?


    2. Will DS100KR800 work for SFI signals?


    3. Can TI recommend a multiplexer to branch out SFI signals? I am thinking of SN65LCP114.

     

  • 0 in reply to David Escandon
    TI__Mastermind 20820 points

    Hi Dave,

    When designing a system and considering what signal conditioning techniques to use the characteristics of the system are the deciding factor for using Pre-Emphasis/De-Emphasis or receiver equalization. Pre-Emphasis/De-Emphasis is typically used if noise is a big factor because receive equalization amplifies transmitted noise. If noise is present on the channel and it is in the optimal frequency range of the equalizer that noise will be boosted along with the signal. Receive equalization is typically used if cross talk and jitter are a big factor. There are benefits to both techniques though so often many system designer choose to use a combination of both Pre-Emphasis/De-Emphasis and receive equalization. So saying that one part is better than another because it has De-Emphasis really is not correct because it depends on the system needs.

    Some of the differences between the 800 and the SN65LVCP1414 are that the SN65LVCP1414 is protocol-agnostic while the 800 is meant for the KR standard, the SN65LVCP1414 is a linear equalizer and the 800 is a limited equalizer, lane to lane skew for the SN65LVCP1414 is typically 8ps while the 800 is 25ps and part to part skew for the SN65LVCP1414 is 50ps max while the 800 is 40ps typically. Also, being that the SN65LVCP1414 is a linear equalizer it is transparent to reflections where as the 800 will pass reflections down stream as noise.

    When looking at the data sheet for the 800 I do not see anything to tell me that it will not except SFI signals.

    The SN65LVCP114 would be a good choice for you application because it is protocol agnostic like the SN64LVCP1414  and it will work with the SFI signals as well.

    Regards,

    Mike