Clarifing example for Packaging EGG

Hello Fellow IBISains:

     As promised, here is a (I hope) clarifying example of how one would
describe a package using the proposed xmission line package concept.
In this example I've listed the rules for describing 'sections', and
I've also added a [Unit Length] keyword. Why? Read on.....

     Suppose you have a package with the following pinout:

____
    |-------- Pin1 sig1
    |-------- Pin2 sig2
    |-------- Pin3 GND
    |-------- Pin5 sig5
    |-------- Pin6 sig6
    |-------- Pin7 sig7
    |-------- Pin8 PWR
    |-------- Pin9 sig9
    |-------- Pin10, sig10
____|

     Each package stub (for the signals) is modeled as follows:

DIE--@@@@@@@@--ZZZZZZZZZZZZZZZZZ--zzzzzzz
     bondwire Trace Pin
     (lumped L) (coupled xmission (uncoupled xmission
                  line) line)

Also assume that the GND and PWR connections are modeled as a
lumped 2.0n inductance.

     This package would be described as follows:

----- content of .pkg file --------

[IBIS Ver] 2.1
[File name] example.pkg
  .
  .
  .
[Define Package Model] 10pin_pkg
  .
  .
  .
| First, I believe a [Unit Length] keyword is needed. I realize that
| as long as all the L/R/C parameters are given in terms of
| unit length, and the physical length is specified in that same, consistent
| unit (inches, cm, etc.) one can calculate the propagation velocity or
| time delay of the section. However, the
| user is going to be integrating this package description into the
| boards netlist or topology. Therefore, the user has to know what units
| the package description is in so the board extraction can use the same.
| Permissible values are 'in', 'cm', 'ft'.
|
[Unit Length] in
|
|
[Number of Pins] 10
|
|
[Number of Sections] 3
|
| In the example above each package stub has three sections.
| The sections are in series and represent the following elements; the
| bondwire (modeled as a lumped inductor), the trace between the bondwire
| and the external pin (modeled as a coupled transmission line), and the
| external pin (modeled as a non-coupled transmission line). The pin
| number keyword is used to describe each section.
|
| For reference, here are the rules for section descriptions and using
| the the Len:, C:, L:, R: and Matrix arguments (Thanks to Kellee
| Crisafulli for suggesting the Matrix argument.)
| 1. Each section description is separated by a comma
| 2. The legal argument combinations are
| a) If the [Number of Sections] keyword is absent, then NO arguments to
| the [Pin] keyword are permitted. It is assumed that there
| is one section of lumped elements whose values are listed under
| the [Matrix] keyword. This is the backwards compatibility option.
| a) Len: and a single 'Matrix' argument. The L, R and C values are
| listed in the Matrix description of that section.
| b) Len: and any combination of the L:, C: and R: arguments. This
| option is for modeling uncoupled transmission lines.
| c) No Len: and any combination of the L:, C: and R: arguments. This
| option is for modeling lumped elements.
| d) Specifying a length of zero (i.e. Len:0) is permitted.
| 3. When a non zero length is specified then L:, R: and C: must be expressed
| in terms of unit length.
| 4. A consistent unit of length (i.e. inches, cm, feet, etc.) must
| be used throughout the package file.
|
|
[Pin Number]
Pin1 Len:0 L:1.2n, Len:1.2 Matrix, Len:0.47 L: 8.35n C:3.34p R:0.01
Pin2 Len:0 L:1.2n, Len:1.2 Matrix, Len:0.47 L: 8.35n C:3.34p R:0.01
Pin3 Len:0 L:0n , Len:1.2 Matrix, Len:0 L:0
Pin4 Len:0 L:1.2n, Len:1.2 Matrix, Len:0.47 L: 8.35n C:3.34p R:0.01
Pin5 Len:0 L:1.2n, Len:1.2 Matrix, Len:0.47 L: 8.35n C:3.34p R:0.01
Pin6 Len:0 L:1.2n, Len:1.2 Matrix, Len:0.47 L: 8.35n C:3.34p R:0.01
Pin7 Len:0 L:1.2n, Len:1.2 Matrix, Len:0.47 L: 8.35n C:3.34p R:0.01
Pin3 Len:0 L:0n , Len:1.2 Matrix, Len:0 L:0
Pin9 Len:0 L:1.2n, Len:1.2 Matrix, Len:0.47 L: 8.35n C:3.34p R:0.01
Pin10 Len:0 L:1.2n, Len:1.2 Matrix, Len:0.47 L: 8.35n C:3.34p R:0.01
|
| The bondwire is described as 'Len:0 L:1.2n' -- a 1.2nH lumped
| inductance. The package trace (section 2) is a coupled transmission line
| so is described using the Len: and Matrix format. Section 3, the
| actual pin, is described as 'Len:0.47 L:0.835n C:3.34' -- an
| uncoupled transmission line 0.47 'units' long with
| 8.35nh/unit_length of inductance and 3.34pF/unit_length of capacitance.
| Also, note the power and ground connections (pins 3 and 7).
| As mentioned above these stubs are modeled as a lumped inductor.
| To keep it simple, section 2 MUST still use the 'Matrix' word.
| I have chosen to lump all the inductance into the 'self L' term in
| the matrix and "zero out" the rest of the sections.
| Setting all the values in a section to zero is legal.
|
| Now comes the matrix description. It is assumed that pins 1 and 2 are
| isolated (by the GND connection) from pins 4, 5, 6 and 7, which are in
| turn isolated (by the PWR connection) from pins 9 and 10. A sparse
| Matrix format is used. To save typing I am only going to show the C
| matrix.
|
[Model Data] section 2
[Capacitance Matrix] Sparse_matrix
[Row] 1
1 1.0p
2 1.5p
[Row] 2
2 1.7p
[Row] 3
3 0.0p | the L matrix would show the self inductance of the stub 3
[Row] 4
4 5.2p
5 3.7p
6 1.1p
7 0.1p
[Row] 5
5 2.7p
6 1.0p
7 0.9p
[Row] 6
6 2.1p
7 1.1p
[Row] 7
7 3.3
[Row] 8
8 0.0p | again, use the L matrix to show self inductance
[Row] 9
9 1.0p
10 1.5p
[Row] 10
10 1.7p
|
|
| Then follows the Inductance matrix (and R matrix if needed).
|

     I hope this example clarifies my proposal. Hope to hear from
everyone Friday.

       Best Regards,
       Stephen
Received on Thu May 4 15:29:26 1995