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LVCP412A in series?

TI Lady
Genius 4025 points


we currently have a “long” SATA path with two LVCP412A’s in series, and this is working fine.  My question is, can three LVCP412A’s be used in series?

  • 0
    TI__Expert 6745 points

    LVCP412A will equalize the input signal.  This equalization is not retimed but re-driven.  Any random jitter will accumulate along the full path of the signal and cannot be compensated by the LVCP412A.  It is possible that the signal at the final sink will have too much jitter to recover the signal correctly.  This is really more of a system level issue and not specifically attributable to the 412A.  Is there a reason for the third 412 to be added?

  • 0 in reply to Ken Shaw
    Genius 4025 points

    This is my SATA path:

     

    Host ßà Backplane Connector ßà Backplane ßà SATA Mux ßà SATA Cable ßà Backplane Connector ßà Drive Connector

     

    I have one 412 at each green point above.  I’m considering adding a third 412 at the red point above, especially since the backplane connector at that point is low performance.

     

  • 0 in reply to TI Lady
    TI__Expert 6745 points

    If you are considering "squaring up" the signal before you connect to a  poor (low performance) , I am not sure this would be be a good solution.  Poorly designed connectors will create signal integrity issues.  Signal integrity gets worse if the signal connected to this poor connector has high frequency content which is "basically" what the 412 is doing (yes, in addition to correcting for data dependent jitter or ISI).  If you could design the system so that this could be implemented in a way that with only a bill of material change you could try it out and then make you decision as to the direction you would like to go, would be nice.   If this is not a clean option (good layout option), then I would recommend not adding the third 412.