A correction, to be clear:
Unused_port_termination_mode=<open | common | per_port | reference>
Radek
From: BIERNACKI,RADEK (K-Sonoma,ex1)
Sent: Wednesday, October 4, 2017 11:43 AM
To: 'Walter Katz' <wkatz@xxxxxxxxxx>; michael.mirmak@xxxxxxxxx;
IBIS-Interconnect <ibis-interconn@xxxxxxxxxxxxx>; IBIS-ATM
<ibis-macro@xxxxxxxxxxxxx>
Subject: RE: [ibis-macro] Conclusions regarding unterminated ports from today's
meeting
Hi All,
Sorry I had to leave earlier and I see that not all my preferences were
considered - I really do not see the logistics for excluding them.
Walter, regarding your comment below I would say: not quite. What you phrase as
"elegant" I would phrase as "EDA implementation lazy", as you just want to
extract a submatrix. But that will not always work anyways. For that to work
you need the Touchstone file to contain the single-ended S-parameter data. It
will not work if the file contains Z or Y parameters, nor any mixed-mode data.
In all cases when the simple extraction does not work the EDA tools can still
do the matrix reduction, if desired. That includes the other two possible means
of defining the terminations (a common resistance value, and per port
resistance values).
To accommodate all the options that we want to give to the model vendor and to
make the syntax easy to check we need two parameters, for example
Unused_port_termination_mode=<open, common, per_port, reference>
with string literal entries, followed by another parameter, required when the
second or the third option is specified
Unused_port_termination_values=..... (for example: ...=50, 48.5, 0.15)
The list above would contain just one value for option "common", or exactly the
number of unused ports for the "per-port" option, and would be applied in the
order of unused ports.
I value the "per_port" option far more than the "reference" option for the
reasons I mentioned yesterday (including being unambiguous and more flexible),
as the reference impedances reflect the measurement, not the usage environment.
I would still consider the default of "open" if the parameter
"Unused_port_termination_mode" is not specified, in other words I would make it
optional.
Radek
From:
ibis-interconn-bounce@xxxxxxxxxxxxx<mailto:ibis-interconn-bounce@xxxxxxxxxxxxx>
[mailto:ibis-interconn-bounce@xxxxxxxxxxxxx] On Behalf Of Walter Katz
Sent: Wednesday, October 4, 2017 4:53 AM
To: michael.mirmak@xxxxxxxxx<mailto:michael.mirmak@xxxxxxxxx>;
IBIS-Interconnect
<ibis-interconn@xxxxxxxxxxxxx<mailto:ibis-interconn@xxxxxxxxxxxxx>>; IBIS-ATM
<ibis-macro@xxxxxxxxxxxxx<mailto:ibis-macro@xxxxxxxxxxxxx>>
Subject: [ibis-interconn] Re: [ibis-macro] Conclusions regarding unterminated
ports from today's meeting
MM,
Termination at reference impedance allows matrix reduction.
Suggested re-write:
Only two options for unused port termination treatments should be permitted in
the Interconnect model specification:
1) Keep unterminated ports open;
2) Terminate the ports before simulation with their corresponding reference
impedances from the Touchstone file, this allows more elegant mathematical
reductions in the matrix data before use
Walter
Walter Katz
wkatz@xxxxxxxxxx<mailto:wkatz@xxxxxxxxxx>
Mobile 303.335-6156
From: ibis-macro-bounce@xxxxxxxxxxxxx<mailto:ibis-macro-bounce@xxxxxxxxxxxxx>
[mailto:ibis-macro-bounce@xxxxxxxxxxxxx] On Behalf Of Mirmak, Michael
Sent: Wednesday, October 4, 2017 12:40 AM
To: IBIS-Interconnect
(ibis-interconn@xxxxxxxxxxxxx<mailto:ibis-interconn@xxxxxxxxxxxxx>)
<ibis-interconn@xxxxxxxxxxxxx<mailto:ibis-interconn@xxxxxxxxxxxxx>>; IBIS-ATM
(ibis-macro@xxxxxxxxxxxxx<mailto:ibis-macro@xxxxxxxxxxxxx>)
<ibis-macro@xxxxxxxxxxxxx<mailto:ibis-macro@xxxxxxxxxxxxx>>
Subject: [ibis-macro] Conclusions regarding unterminated ports from today's
meeting
Based on the discussion in today's IBIS-ATM meeting, is the following summary
of our next steps for Interconnect termination treatments correct?
Only two options for unused port termination treatments should be permitted in
the Interconnect model specification:
1) Keep unterminated ports open; this allows brute-force termination of ports,
or more elegant mathematical reductions in the matrix data before use
2) Terminate the ports before simulation with their corresponding reference
impedances from the Touchstone file
To ensure the model-maker has nominal control of the termination treatment,
Unused_Port_Termination should be reintroduced as a parameter, but as a
required one. It should also have a different structure, with only two
possible arguments:
Unused_port_termination = <open | reference>
If supported, this is parse-able and checkable, but as with many other
parameters, an EDA tool could allow the user to override the setting; this
would violate the spirit of the specification but would not result in a
checkable violation of the syntax.
* MM
