Re: [SI-LIST] : Bad IBIS models!

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From: Richard G. Munden (munden@acuson.com)
Date: Thu Mar 16 2000 - 21:43:15 PST


Another way for for the IC suppliers to view the modeling issue is: The
sooner a design is debugged the sooner it hits the market. The sooner
it hits the market the sooner the customer starts buying parts in
quantity.

I would also like to point out that although the discussion so far has
centered on IBIS models, many customers also need behavioral logic
models. Many parts have reached the level of complexity that makes them
very difficult to design in correctly the first time without a good (at
least bus-level) behavioral model. And one with accurate timing at
that.

Rick Munden

Roy Leventhal wrote:
>
> Brian,
>
> Your questions are challenging. I will do the best I can to respond.
>
> The effect of advertising in different channels is quantified and measured.
> Decision makers need to do the same with regard to any money they spend whether
> it's modeling or any other expenditure such as product quality. Speaking of
> product quality, for years it was ignored because it couldn't be "quantified"
> and related to ROI. Or, so people said. After the semiconductor companies picked
> themselves up off the floor they decided to invest in developing the measures
> (cost of quality, cost of lost sales, etc.) that would tell them the value or
> non-value of efforts in quality. I suspect that an up front investment in first
> developing the measures of value or non-value of efforts in modeling will have
> to occur before the value of efforts in any particular case can be assessed. Of
> course, it took a train wreck before managers in the semiconductor companies
> were even interested in asking and answering the question of value with regard
> to quality. I suspect the same will be true before managers in the semiconductor
> companies will be interested in asking and answering the question of value with
> regard to modeling. Assuming the train wreck occurs, and the managers in
> question get a second chance to compete, I suspect the measures will be similar:
> cost of redoing a model, cost of lost sales, etc.
>
> I have no way at all of putting actual numbers on a given case, as I suspect you
> do not, either. I suspect the folks who quantified the quality issue for
> management have experience that could be called upon. Incidentally, your points
> are identical in spirit with those made and ignored in the industries of autos,
> semiconductors, electronics, etc. I agree, the chief determinant of just how
> important modeling, or quality, or - - - is - is the marketplace.
>
> But, just because management decides a problem, or pending problem, doesn't
> exists doesn't make it so. As engineers, we suspect that the problem is real.
> Heads-up management heeds the warnings and seeks out the reality, or lack of,
> behind them. Fortunately, the marketplace has a way of sorting this all out.
> Trouble is, all of us, prophets and sinners, get squished under the tank treads.
>
> Will the train wreck occur? Perhaps. But, as switching speeds increase it
> becomes more likely that the customer will be unable to sucessfully apply a
> product without modeling it. Remember, modeling is a substitute for
> breadboarding (perhaps through many iterations) which is becoming ever more
> expensive, costly in time-to-market and ineffective in getting to find-and-fix.
>
> So, modeling can be viewed as a product feature. The customer may not be able to
> get his/her product to market within the market window, at an acceptable cost
> and with a quality level that their customers expect. And, modeling has to be
> presented to management as such; a required product feature when that is the
> actual case.
>
> You are correct, nobody can afford to expend infinite resources on every good
> cause. Further, the customer won't pay for it or care past a certain point.
> Also, I recommend to my designers that they use the concepts of desensitising
> their designs, design margins, etc., instead of asking for unreasonably
> complicated and accurate models. Customers have their part to play too. I.e.,
> back to your point of quantifying the choices to be made.
>
> But, let's get real. The nature of the complaints on this reflector on this
> subject have to do with plain shoddy work or no work at all. Not with the fine
> or esoteric points of modeling.
>
> Best Regards,
>
> Roy
>
> Brian Young <briany@ibmoto.com> on 03/16/2000 02:08:39 PM
>
> Roy,
>
> I agree with your points, but I would like to put some spin on them.
>
> 1. Suppliers spend millions on advertising because they have proven
> to themselves a hard link between increased advertising and increased
> sales. Advertising is scaled back in media channels that yield little
> sales increase.
>
> With respect to IBIS modeling, there is little history to guide the
> investment. Will you spend millions and see no increase in sales? If
> you spend millions and see an increase in sales, how much of the
> increase
> was due to IBIS and how much to other factors?
>
> I would like to put a marketing wrapper on an argument for investment
> in IBIS modeling. How can I put some numbers on it? Managers want
> to know what the return will be on their investment.
>
> 2. The costs associated with bad or non-existent modeling is just as
> you say: apparent and hidden. That is, not quantified. How can the
> numbers be quantified?
>
> Finally, things that are worth doing are worth doing well. The problem
> is selecting the things you will do out of the nearly infinite space
> of things that are worth doing. You can't do everything.
>
> Brian
>
> --
> ***************************************************************
> * Brian Young phone: (512) 996-6099 *
> * Somerset Design Center fax: (512) 996-7434 *
> * Motorola, Austin, TX brian.young@motorola.com *
> ***************************************************************

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