1 Reply Latest reply on Oct 15, 2014 8:45 PM by cmaryan

    ddr3 simulation

    agxinmj

      hai

                 I simulated a data line with gnd as reference in both the layers

      and with gnd and its own power as reference

      with some other power net as reference

      all are providing the same results

      does hyperlynx consider the effect of return currents

      if it includes the effect of return currents how to enter

      regards

      AGXIN .J

        • 1. Re: ddr3 simulation
          cmaryan

          No, HL does not consider return currents. A power plane and a GND plane are equivalent as far as HyperLynx is concerned. For the most part that's a reasonable approximation, as long as the GND and power plane are well decoupled (lots of caps).

           

          Beware though that in the real world, a power plane will be noisier. That's why Micron recommends referencing DQ/DQS to GND. Address/cmd can be referenced to Vdd if necessary - because A/C is less sensitive to noise (larger bit period).