All,
This discussion of A_gnd has gotten way out of control, unnecessary and a
huge waste of time.
A_gnd should be defined as a Global Simulator Reference Node (e.g. Node
0).
* If a simulator supports IBIS-ISS then it must support Node 0.
* BIRD 189 is based on IBIS-ISS.
It is very important to note that the model maker who creates BIRD 189
models can choose to
* Not use A_gnd in his Interconnect model terminals and not use Node
0 in any of his IBIS-ISS files.
* Use A_gnd in his Interconnect model terminals or use Node 0 in any
of his IBIS-ISS files.
* The currents that go to the component "ground pins" (as defined in
the Component Data Book)" may not account for the currents that go to Node
0.
Almost universally, package interconnect, board interconnect and connector
interconnect SPICE models use Node 0, and almost universally power aware
simulations are "ground base".
I would like to make the following motion:
1. IBIS 189 should state that A_gnd is the Simulator Reference Node
(Node 0 in IBIS-ISS)
2. We add the following Note:
a. Using A_gnd as Interconnect Model Terminals or Node 0 in IBIS-ISS
subckts may not account for all currents going to "ground" pins, and
therefore potentially introduce simulation results when doing power aware
simulations that are not ground based.
Anyone can write a supporting document on why it is better to make models
that do not use A_gnd or Node 0. This does not belong in the BIRD, but can
be submitted as a supporting document to the BIRD.
Walter
Walter Katz
<mailto:wkatz@xxxxxxxxxx> wkatz@xxxxxxxxxx
978.461-0449 x 133
Mobile 303.335-6156
