Subject: Re[2]: Connector spec swathing

From: [email-masked]
Date: Thu, 15 Jun 2000 06:37:10 -0500

Fred,

I am sure that if you have this question, so do others... as such I have
prepared a fairly lengthy reply.

The "basic" answer to the question is...

Find a FIELD simulator that can generate a 100 pin connector model from a
connector with a general current path length of around 2.5cm.

Make sure it is a true 3D simulator.

OK... now find one that can do such using less than 8GB of RAM and 4 xxxx GHz.
processors
  -  This is pretty much what one might call a high end PC/Workstation.  Maybe
even not "typical" hardware.

OK...  Using what has been found above...  have the problem solve in the FIELD
simulator in less than a week.  (BTW, a week is solve time, it does not include
reports, empirical confirmation, or support documentation)

OK...  now put that full matrix model that is generated into a circuit
simulator....  Setup the rest of the problem....  go away for the weekend...
comeback Monday....  still not done...  Comeback Wednesday...  Ooopps  found out
that a termination resistor was misplaced... restart the simulation.

The point is...  connector companies would be perfectly happy with smaller
models...

But from what I have been told my customers which are the same as many SI
simulators NEED to be able to model 50, 100, 200, 500, 1000, 5000 pins... (Yes,
these are all real connector sizes today).

As a work around for this problem.... we suggest the preverbal "critical net
analysis". Which will still take 8 hours to solve using something in the order
of a 40 pin connector model.

Also,  I as a connector manufacture make parts with different circuit sizes...
sometime from 10 to 1000 in 10 pin increments...  OK... there we have 100
models...  Lets say we just go up to 100 pins...  that is 10 models... at 3 days
AVERAGE per model (smaller models take less time)...  that means one month of
FIELD SIMULATION time...  and we STILL  can not support any thing over 100 pins.

 Not to mention that connector companies have about 40,000 different product
lines.. lets say conservatively that only 1% of the 40,000 require models... 
That's 400.... a conservative estimate would be that there are 10 circuit sizes
for each of those 400 connectors...  as such 4,000 different models.  OF EACH
Type.  There are three basic types Single Line models, MultiLine Models, and
Cascaded Models...  then there are TWO VERSIONS of each type... distributed and
lumped...  grand total 24,000 SPECIFIC models.

But wait,  Now model makers and simulators also have to database and revision
control the models.

Point being...  an auto swath will give end uses access to more models with more
pin options than they ever had before (to answer the customers requests). And
GREATLY reduce the redundancies such that the 24,000 models above can be done in
1 model per connector family.. or 400 files.

_gus: 630-527-4617

____________________Reply Separator____________________
Subject:    Re: Connector spec swathing
Author: fred <[email-masked]>
Date:       6/15/00 1:33 AM

I know the connector specification committee has spent much time and effort in
comming up with the specification.  However the current swat matrix approach
seems overly complicated and technically less than desirable.  Why not give the

full matrix and let the simulation SI tool decide which part of the matrix to
choose
for simulation based on what pin and coupling is desired. We (simulation
vendors)
only need the data. We can decide how and when to use what.  What we need is
the committee to do is identify the connector pins to the matrix diagonal
entrys. If
the connector is very large in terms of number of pins then whether one gets a
full
or sparse matrix will depend on the field solver capabilities. This is not
intended to
be critical of the committee which has worked long and hard to come up with a
spec
in the first place while hence keeping everybody happy.

Best Regards,

Kellee Crisafulli wrote:

> Hi Chris,<SNIP>

---

From: "Chris Rokusek" <[email-masked]>
Date: Thu, 15 Jun 2000 09:27:55 -0700

Gus,

Given that some companies actually do possess the tools to create Full
Matrix connectors (& packages) accurately and efficiently and given that
simulators MUST come up with algorithms to reduce this full matrix (perhaps
efficiently with an accuracy tradeoff), simulator companies are just trying
to avoid extra work in having to write two algorithms that do very similar
things--one to expand the swath to arbitrary pins and one to reduce the full
matrix to arbitrary pins.  Many of us prefer to solve the most
general/accurate problem first (Full Matrix).

I don't think we're saying "don't use the swath", I think all we're saying
is provide us with a recommended algorithm (and perhaps build it into the
parser) for expanding the swath into a full matrix so that each simulator
can potentially get the same answer for the most general case.  It seems
like that would keep everybody happy.

Chris Rokusek
Innoveda

> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]]
> Sent: Thursday, June 15, 2000 4:37 AM
> To: fred
> Cc: Kellee Crisafulli; IBIS Mailing list
> Subject: Re[2]: Connector spec swathing
>
>
> Fred,
>

---

From: fred <[email-masked]>
Date: Fri, 16 Jun 2000 03:58:58 -0700

You are confusing modeling and simulation. I'm not suggesting that you model the
full connector if its large. Rather, if you model only a portion then I prefer that
you
tell me that and give me that answer rather than bogus something. If you feel that
the
connector is repetative then put together the model such that I get a full matrix
type
or sparse matrix. This means I should have representative coupling between any
two or three pins as you may feel necessary. But I need the full model.
Verification
of the model is entirely a different animal and  I cannot see how the swat helps
with
that process at all.

IF you give me the full model I may not attempt to simulate the whole thing. You are

only giving me information. Its up to me to use that wisely. For example if I choose

to simulate through connector pin number 5, I as a user may wish to consider only
coupling to pin 7 and pin 3.  I can make that decision during simulation coupling
setup. The important thing is that I can get decent accurate data for the pins I
wish
to consider during simulation. If you give me the full model I will then PICK the
data I wish to simulate from the full data you gave me.  However giving me a swat
ensures that for some pins I will lose some coupling.  It also ensures confusion and

abiguity.

Please note that the swat does not help your modeling. It's only a way to present
the
data. So the issue of modeling the full connector versus giving me a full matrix is
a
seperate one. We're talking about how to present the data not field solver
algorithms.

Best Regards,