Re: another ebd modeling question

In the .ebd file, we can describe the board net topology
(ex, from memory module tab to DRAM I/O buffer) according to
the IBIS 3.2 electrical board description syntax. In that .ebd file
we describe the I/O buffer as reference designator like "U8.12"
and the search path of that device IBIS with keyword [Reference
Designator Map].
When the simulator use .ebd file, first it imports board net
topology and then it searches required device IBIS at the path
described in the [Reference Designator Map].

====================================
Jongho Kang
E-mail : jhkang@hynix.com
Office : 82-31-639-1972
Shop : 82-31-630-2328/2977
Mobile : 018-221-7806
Product Application Engineering,
Memory R&D, Hynix Semiconductor Inc.
====================================
  ----- Original Message -----
  From: Hailong Wang
  To: Jongho Kang
  Cc: ibis-users@eda.org ; Kris Young
  Sent: Thursday, May 31, 2001 3:55 PM
  Subject: Re: another ebd modeling question


  Hi,
      Could you tell me how to use the .EBD file and the relation between the .EBD and .IBS files. Thanks in advance.
    
  Jongho Kang wrote:

    Kris,
    Did you figure out what configuration of L and C is used when Len=0 and
    L and C is specified ?
    I'm in the same situation as you was. I'm trying to describe C-L-C lumped
    circuit in the EBD.
    If you figured out , please let me know.

    Thanks,
    Jongho Kang

    ----- Original Message -----
    From: Kris Young <kyoung@phaseiv.com>
    To: Mike LaBonte <mike@labonte.com>
    Cc: <ibis-users@eda.org>
    Sent: Friday, April 20, 2001 11:34 PM
    Subject: RE: another ebd modeling question

    Mike,

    I have been using the PSPICE distributed transmission line model, and you're
    right, it's very convenient to plug in the values from the EBD file. I was
    very relieved when I figured that out.

    My question concerns the special case in the EBD file when LEN=0.
    Supposedly this requires the use of a lumped element. For instance, when
    LEN=0 and R=0.003, it is specifying a series 3 mOhm resistor. In the file
    I'm simulating, there are a few cases where LEN=0, and L and C are
    specified. I'm trying to figure out what configuration of L and C is
    specified by such a description.

    Kris Young
    Phase IV Systems, Inc.
    Huntsville, AL

    -----Original Message-----
    From: Mike LaBonte [mailto:mike@labonte.com]
    Sent: Friday, April 20, 2001 5:39 AM
    To: Kris Young
    Cc: ibis-users@eda.org
    Subject: Re: another ebd modeling question

    Kris,

    Why not use the PSPICE transmission line model? It is a true distributed
    transmission line model, so you don't have to be concerned about how
    to do the lumping. Also, it accepts per-length RLGC values. For example:

    T3 one_end 0 other_end 0 LEN=1 C=3.1p L=1.05p

    PSPICE accepts the notion that LEN is not in any particular units,
    same as EBD. Of course you can add R= and G= for lossy lines, too.

    That said, if you still need to create a lumped model, try splitting
    the series elements in two to make it symmetric. For example, use
    two inductors, each with half the inductance. This way a signal going
    one way comes out identical to the same signal going the other way.
    You can leave the middle series elements unsplit.

    Mike LaBonte

    Kris Young wrote:
>
> I have one more question for the IBIS gurus out there. I'm using Pspice
    to
> model a signal path from an EBD file. I've figured out everything except
> what to do when the length is zero and there's an L and a C. When I look
    at
> the classic lumped lossy line (taking R=0 and G=inf), the series L comes
> first and then the parallel C. However, when I look at the classic
    lossless
> case, the parallel C comes first, and then the series L.
>
> Since the impedances of these configurations differ, which one should I
    use.
> I can only guess, but it should be clearer than that, right? Would the
> lossy case be the one to use, even if there's no R?
>
> Thanks again,
>
> Kris Young

--
Best Regards.
Hai-long Wang
Tel:021-62837026x228
Avant! Shanghai R&D Center, 16th Floor, SunTong InfoPort Plaza
No.55, West Huaihai Road, Shanghai, 200030, P.R.China
    

 
Received on Thu May 31 04:32:39 2001