1 Reply Latest reply on Aug 3, 2011 11:10 AM by weston_beal

    Question regarding technote MG543184 compensated flight time measurements in DDRx wizard

    bpsplett

      I understand the procedure that is being explainded here but am confused as to the outcome......the compensated Trise  is added into the Tprop from the driver to receciver or it is called out as an added measurement showing the engineer what the tco is for that device?

        • 1. Re: Question regarding technote MG543184 compensated flight time measurements in DDRx wizard
          weston_beal

          The important point is that the model does NOT have Tco (clock to output delay), nor any way to derive it. We get Tco from the driver data sheet. Then we add the Tprop (compensated flight time) to Tco in our timing margin calculation for a common-clock bus. This particular technote explains why it is generally not necessary to calculate compensated flight time in DDR data-to-strobe timing. The DDR timing is not common clock, but relative, sometimes called source synchronous.

           

          There is a more general and detailed discussion of compensated flight time in technote MG82617.