5 Replies Latest reply on Jul 20, 2015 8:51 AM by matthias.cosaert

    SI simulation differs with real measurement a lot

    nate.wang

      Hi Sir,

       

      I am a beginner of Hyperlynx, try to do SI simulation as a reference for my next version of PCB design.

       

      On my current PCB, there are 64 LVDS interfaces, all running at maximum 960Mbps, from eight ADC (ADI AD9279) to a FPGA (Xilinx Virtex-6).

       

      Below is real measurement of one of the LVDS interface ( at 250Mbps, at FPGA side ) :

      250Mbps.png

       

      And below is SI simulation result from Hyperlynx,

      as you can see, simulation result is totally different from the real measurement.

      s1.png

      stimulus setting as below :

      s2.png

      simulation trace :

      board.png

       

      On the other hand, we had previously assign a 3rd party company to perform SI simulation on these LVDS traces, below are two of the results :

       

      at 480Mbps :

      si-480Mbps.png

       

      at 960Mbps :

      si-960Mbps.png

       

      They use exactly the same IBIS models of mine in Hyperlynx(also attached in this post), so I do think my problem is related to parameter setting in Hyperlynx (?).

       

      Any comment is appreciated, thanks in advance.