My experience is mainly with companies developing test and measurement fixtures
PCBs, is that now compared with the past several of them will provide SI/PI
services which basically consist importing the layout or some part of the
layout and then doing multiple simulations and generating dozens of slides.
The customer usually is very impressed with the amount of data and since
usually the results looks good he is happy. In some cases he asks to simulate
X different scenarios and they will do it even they make no sense (e.g.
optimizing ad nauseam a 3rd order item while neglecting critical items). The
customer engineer then has several nice pictures to show his boss, etc... but
most of the cases he himself has no real SI/PI experience to judge the results
(although most of the times he might think differently regarding his SI/PI
skills).
But at the end neither the test fixture vendor or the end customer will do any
measurement to correlate or tune the simulations. In fact I think several of
these companies have done multiple simulations projects but never correlated
the data. The usual answer I hear is always "we do not have the equipment".
Even more interesting is when some of these companies show on their brochures
that they have a state of the art VNA/TDR but when you talk with them and ask
about their probing/de-embedding approach you see they have no clue. They
basically bought the instrument because it helps with selling their services
but they prefer to stay away of doing any measurements because it is very
different from just running a SW simulation.
If there are no major problems (nota that usually the problem needs to jump on
the engineer face because he might have a problem on the PCB test fixture and
simply do not realize it assuming that the DUT performance is what he gets
because no measurements were done on the PCB), no-one thinks about correlating
the simulations because usually the customer engineer will be very busy doing
his measurement tasks.
Then when for some reason a correlation measurement is needed they ask how can
it be done and if I tell them for example to buy Istvan book to understand how
to do a proper PDN measurement they complain they have no time to read a book,
it is too complicated and anyway they need the measurement today, etc....
In my opinion if a vendor providing SI/PI services also shows they have
experience with measuring and tuning/correlating their simulations then my
trust level on them increases significantly. E.g. a vendor that comes to me and
says something like "on our simulation we change the loss tangent of the
dielectric material to value X because we know from previous projects
measurement that using the spec sheet loss tangent we do not get a proper
correlation since the results are too optimistic).
Regarding how they survive, getting good SI/PI consulting is expensive and
there are teams that never did SI/PI analysis before and now they need to do it
(or think they need it) because they are working at higher data rates so they
choose a cheaper service or their usual vendor provides now this service for
free. But even at these higher data rates a lot of the times the projects work
independent if the initial simulations are wrong. This is why I think they keep
surviving since when the customer has real problems the attention goes on how
to fix the problem and not why the initial SI/PI simulation was wrong and this
usually happens in a panic and very hectic mode at least in my experience.
Jose
-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On
Behalf Of Ken Cantrell
Sent: Wednesday, August 05, 2015 6:15 PM
To: twesterh@xxxxxxxxxx; si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: commodity
Todd, et al -
For all of us gray beards ( or getting there), the trend on the List has
shifted from "get input from a world class SI Engineer", to "do my work for
me". The old paradigm/assumption was that you would do "due diligence"
before you submitted a question. Do your homework first. This has by and
large disappeared. A lot of people don't even consult their product or
software FAE first. Or more absurdly, few seem to know how to even google
anymore. There are exceptions of course, but the problem is that they are
exceptions, outliers in the distribution. There are no stupid questions. I
would modify this to there are no stupid questions if you have done your
research first. Right now, there are a lot of stupid questions, and a lot of
lazy "SI" engineers.
Those of you, young or old, that do due diligence are exempted from the above.
Keeping it 100,
Ken
-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On
Behalf Of Todd Westerhoff
Sent: Wednesday, August 05, 2015 9:24 AM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: commodity
Istvan,
I'd like to pose a counter-question.
Are automotive mechanics a commodity?
And if so, why is an affordable, affable, available master mechanic such a rare
find?
Todd.
Todd Westerhoff
VP, Semiconductor Relations
Signal Integrity Software Inc. . www.sisoft.com
6 Clock Tower Place . Suite 250 . Maynard, MA 01754
(978) 461-0449 x124 . twesterh@xxxxxxxxxx
"I want to live like that"
-Sidewalk Prophets
-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx]
On Behalf Of Istvan Nagy
Sent: Wednesday, August 5, 2015 2:26 AM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] commodity
Hi,
Did signal integrity engineering become a commodity?
Or is this trend about to slap someone in the face?
I thought it used to be a professor or scientist job for the best and
brightest, but nowadays all companies keep hiring people for their SI teams in
large quantities. Most job postings are like "fresh graduate with 3yr
experience", that's all that's required. The "expert" is not part of the
equation anymore?
Did it become that simple that any fresh graduate can do what 10 years ago only
the smartest people could do?
I got quotes from some service/contractor companies doing SI simulations for us
on their Ansoft tools (for a lot of money), but "what to simulate"
or "how to interpret the results" was either not covered or was seriously
misguided.
The same might have happened to "engineering" some years earlier. Is it the
same, or this time it is different?
Some threads here on si-list in recent years seem (to me) to reflect that too.
Regards,
Istvan Nagy
(I am not really an SI-engineer, but a HW/product/board designer)
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