All,
Bob, Arpad, and I had a very interesting e-mail thread on the meaning of
life (strike that the meaning of the following two lines in IBIS 6.0).
. "If [C Comp Corner] is present, its value or values override
any other C_comp* representations."
. "It is not illegal to include the C_comp subparameter together
with one or more of the remaining C_comp_* subparameters, but in that case
the simulator will have to make a decision whether to use C_comp or the
C_comp_pullup, C_comp_pulldown, C_comp_power_clamp, and C_comp_gnd_clamp
subparameters."
Based on these two line, what do you think the model maker expects the EDA
tool to do when encountered with the following Model when running the Min
(aka Slow, Weak Corner:
[Model] C_comp?
C_comp_pullup 2.0p 1.0p 3.0p
[C Comp Corner]
C_comp_pulldown 4.0p 8.0p 2.0p
There are the following possible expectations:
1. Capacitor to A_puref 1.0pF
2. Capacitor to A_puref 3.0pF
3. Capacitor to A_puref 3.0pF|1.0pF (Note treat
C_comp_pullup as a range and try both extremes)
4. Capacitor to A_pdref 8.0pF
5. Capacitor to A_pdref 8.0pF Plus Capacitor to A_puref
with the values in expectations 1., 2. or 3.
If we can all agree to one of the above 5 possible expectations, then we
can write a BIRD to clarify the above text in IBIS 6.0.
If we cannot agree, then we should at least publish to the IBIS model
making community that if the model is to communicate accurately what the
model maker expects the EDA tool to do, there should be no [Model] C_comp*
sub-parameters, and the model maker should only use C_comp_*
sub-parameters.
Walter
Walter Katz
<mailto:wkatz@xxxxxxxxxx> wkatz@xxxxxxxxxx
Phone 303.449-2308
Mobile 303.335-6156
