2 Replies Latest reply on Aug 5, 2011 2:40 PM by joseph.aday

    ODT in DDR2+ SRAM IBIS Model

    joseph.aday

      Hi, the DDR2+ SRAM parts are supposed to have ODT on the DATA lines... but I don't see it in the ibis model.  I see it on the BWS and K/K* though.

         

      Example from ddr2pb2l25_cy21xx.ibs (You can see where it says what the driving output impedance is, but the input impedance is unknown):

         

      [Model Selector]    DATAIO
      |
      DATAIO50_TT_1.5   DATAIO models (50ohms) at TT conditions - 1.5V I/O
      DATAIO50_FF_1.5   DATAIO models (50ohms) at FF conditions - 1.5V I/O
      DATAIO50_TSF_1.5  DATAIO models (50ohms) at Typ Slow Fast conditions- 1.5V I/O
      DATAIO30_TT_1.5   DATAIO models (30ohms) at TT conditions - 1.5V I/O
      DATAIO30_FF_1.5   DATAIO models (30ohms) at FF conditions - 1.5V I/O
      DATAIO30_TSF_1.5  DATAIO models (30ohms) at Typ Slow Fast conditions- 1.5V I/O
      DATAIO40_TT_1.5   DATAIO models (40ohms) at TT conditions - 1.5V I/O
      DATAIO40_FF_1.5   DATAIO models (40ohms) at FF conditions - 1.5V I/O
      DATAIO40_TSF_1.5  DATAIO models (40ohms) at Typ Slow Fast conditions- 1.5V I/O
      DATAIO60_TT_1.5   DATAIO models (60ohms) at TT conditions - 1.5V I/O
      DATAIO60_FF_1.5   DATAIO models (60ohms) at FF conditions - 1.5V I/O
      DATAIO60_TSF_1.5  DATAIO models (60ohms) at Typ Slow Fast conditions- 1.5V I/O
      DATAIO70_TT_1.5   DATAIO models (70ohms) at TT conditions - 1.5V I/O
      DATAIO70_FF_1.5   DATAIO models (70ohms) at FF conditions - 1.5V I/O

         

      Thank you.

        • 1. Re: ODT in DDR2+ SRAM IBIS Model
          content.librarian

           Hi Westec,

             

                    The data inputs also have ODT.Please confirm whether you are referring to the latest IBIS model on the web in link below:

             

          http://www.cypress.com/?rID=48344

             

          Below are the ODT buffer model in the IBIS model.

             

           

             

           

             

          [Model Selector]    INPAD

             

          INPUT525_TT_1.5  INPUT models(52.5ohms) at TT conditions - 1.5V I/O 

             

          INPUT525_FF_1.5  INPUT models(52.5ohms) at FF conditions - 1.5V I/O 

             

          INPUT525_TSF_1.5 INPUT models(52.5ohms) at TypSlowFast conditions- 1.5V I/O

             

          INPUT75_TT_1.5   INPUT models (75ohms) at TT conditions - 1.5V I/O 

             

          INPUT75_FF_1.5   INPUT models (75ohms) at FF conditions - 1.5V I/O 

             

          INPUT75_TSF_1.5  INPUT models (75ohms) at TypSlowFast conditions- 1.5V I/O

             

          INPUT90_TT_1.5   INPUT models (90ohms) at TT conditions - 1.5V I/O 

             

          INPUT90_FF_1.5   INPUT models (90ohms) at FF conditions - 1.5V I/O 

             

          INPUT90_TSF_1.5  INPUT models (90ohms) at TypSlowFast conditions- 1.5V I/O

             

          INPUT105_TT_1.5  INPUT models (105ohms) at TT conditions - 1.5V I/O 

             

          INPUT105_FF_1.5  INPUT models (105ohms) at FF conditions - 1.5V I/O 

             

          INPUT105_TSF_1.5 INPUT models (105ohms) at TypSlowFast conditions- 1.5V I/O

             

          INPUT150_TT_1.5  INPUT models (150ohms) at TT conditions - 1.5V I/O 

             

          INPUT150_FF_1.5  INPUT models (150ohms) at FF conditions - 1.5V I/O 

             

          INPUT150_TSF_1.5 INPUT models (150ohms) at TypSlowFast conditions- 1.5V I/O

             

          INPUT525_TT_1.8  INPUT models(52.5ohms) at TT conditions - 1.8V I/O 

             

          INPUT525_FF_1.8  INPUT models(52.5ohms) at FF conditions - 1.8V I/O 

             

          INPUT525_TSF_1.8 INPUT models(52.5ohms) at TypSlowFast conditions- 1.8V I/O

             

          INPUT75_TT_1.8   INPUT models (75ohms) at TT conditions - 1.8V I/O 

             

          INPUT75_FF_1.8   INPUT models (75ohms) at FF conditions - 1.8V I/O 

             

          INPUT75_TSF_1.8  INPUT models (75ohms) at TypSlowFast conditions- 1.8V I/O

             

          INPUT90_TT_1.8   INPUT models (90ohms) at TT conditions - 1.8V I/O 

             

          INPUT90_FF_1.8   INPUT models (90ohms) at FF conditions - 1.8V I/O 

             

          INPUT90_TSF_1.8  INPUT models (90ohms) at TypSlowFast conditions- 1.8V I/O

             

          INPUT105_TT_1.8  INPUT models (105ohms) at TT conditions - 1.8V I/O 

             

          INPUT105_FF_1.8  INPUT models (105ohms) at FF conditions - 1.8V I/O 

             

          INPUT105_TSF_1.8 INPUT models (105ohms) at TypSlowFast conditions- 1.8V I/O

             

          INPUT150_TT_1.8  INPUT models (150ohms) at TT conditions - 1.8V I/O 

             

          INPUT150_FF_1.8  INPUT models (150ohms) at FF conditions - 1.8V I/O 

             

          INPUT150_TSF_1.8 INPUT models (150ohms) at TypSlowFast conditions- 1.8V I/O

             

           

             

          regards

             

          Jayasree

          • 2. Re: ODT in DDR2+ SRAM IBIS Model
            joseph.aday

            Hi Jayasree,

               

            Yes that's a good example model (I've looked at several CIO models... all very similar.) 

               

            The INPAD does have ODT, but is not assigned to Data.  Data use the DATAIO model (the one I pasted.)  Check the [Pin] list:

               

            B2              DQ27              DATAIO  

               

            Thanks again,
            Joseph