[SI-LIST] Re: Using general purpose computer tools to solve SI problems
- From: Dan Bostan <dbostan@xxxxxxxxx>
- To: alan@xxxxxxxxxxxxxxxxx, bmgman@xxxxxxxxxx
- Date: Thu, 30 Sep 2004 09:49:30 -0700 (PDT)
Very nice answer and I must say that I share the same
experiences/uses for Excel.
/dan
--- Alan Hilton-Nickel <alan@xxxxxxxxxxxxxxxxx> wrote:
> Damn lies indeed!
> One of my favorites has been to use Excel to do a
> single-node analysis
> of my power distribution system as a preplanning
> tool to accurately
> estimate the number of decaps you need. Kind of like
> a cheap PowerSI for
> prelayout planning. Of course, you have to make
> reasonable estimates of
> connection inductances for your caps. The good news
> is that if you are
> disciplined, you can feedback the inductance
> information from Power-SI
> or from VNA measurements so that future estimates
> are more accurate. But
> you have to stay aware of your inductance
> assumptions.
>
> Other uses I have made for Excel:
> - Setting up multiple cross-sections for XFX so I
> can do some what-if
> analysis without having to be always as mindful of
> the XFX syntax.
> - Calculating timing constraints and generating
> import files for
> Constraint manager.
> - Keeping track of and generating layout constraint
> sets in APD/Allegro.
> - calculating memory timing register settings based
> on desired speed
> and memory used.
> - planning BGA pinouts, and calculating pin counts
> and power/ground ratios.
> - keeping track of individual chips with lot/bin
> info and test results,
> and relating that to the boards they are in and who
> I've loaned them to.
>
> A long time ago I used to do some contract
> manufacturing, and my
> cost-estimating spreadsheet was usually within 5%.
> Knowing my costs that
> well, I knew how little money I was making - it
> convinced me to get out
> of the business...
>
> As Arpad suggests, Excel is the best CAD tool I
> know!
>
> Alan Hilton-Nickel
>
> Mike Brown wrote:
>
> >John,
> >
> >I'm sure that you have heard the old saw about 3
> kind of lies: Lies, damned lies, and statistics.
> >
> >Modern science has added a 4th kind of lie :
> spreadsheets. ;-)
> >
> >That having been said, I use spreadsheets
> extensively, with HSPICE-extracted buffer and trace
> delays for board-level timing analysis.
> Spreadsheets are a great example of a DIGO unless
> they are well-constructed and reviewed. DIGO?
> Data In, Garbage Out. I've been burned by failure
> to thoroughly review the design of such a
> spreadsheet. Once burned, twice cautious.
> >
> >Regards
> >
> >Mike
> >
> >John Thomas wrote:
> >
> >
> >
> >>I've performed some simple signal
> propogation/loading analysis with
> >>Excel and another engineer later reproduced the
> findings with PSPICE.
> >>I've also performed a 2D field analysis using the
> iterative calculation
> >>functionality of Excel. The graphic
> representation was nice.
> >>
> >>A background heavy in reliability engineering has
> taught me the value of
> >>the spreadsheet as a tool for engineering
> analysis, starting with an
> >>early version of Lotus 1-2-3 (1985 or so). More
> recent experience has
> >>pulled on that knowledge to use it heavily in
> production yield analysis
> >>and machine/process throughput models. Learning
> the power tools,
> >>especially the analysis package and the VB macro
> language, has made
> >>Excel my most-used tool.
> >>
> >>John Thomas
> >>
> >>-----Original Message-----
> >>From: si-list-bounce@xxxxxxxxxxxxx
> [mailto:si-list-bounce@xxxxxxxxxxxxx]
> >>On Behalf Of Ray Anderson
> >>Sent: Monday, September 27, 2004 10:45 AM
> >>To: si-list@xxxxxxxxxxxxx
> >>Subject: [SI-LIST] Using general purpose computer
> tools to solve SI
> >>problems
> >>
> >>
> >>Engineers quite often utilize specialized software
> to solve specialized
> >>problems in their work. A few general examples of
> these tools might be:=20
> >>spice simulators, field solvers, model generators,
> netlist generators
> >>etc. The list goes on and on.
> >>
> >>As has been discussed recently, sometimes more
> general purpose computing
> >>tools such as spreadsheets can be used to
> advantage to solve engineering
> >>problems if applied appropriately. In the example
> of the spreadsheet,
> >>even though the most common use of the tool is to
> automate 'book
> >>keeping' functions, beneath the hood lives a
> powerful math engine and
> >>graphics interface. Quite often those intrinsic
> qualities of the tool
> >>can be utilized in imaginative ways to solve
> engineering problems that
> >>would otherwise require specialized software that
> might not be available
> >>to the user.
> >>
> >>The non-availability might be due to the fact that
> the type of problem
> >>to be solved is uncommon enough that acquisition
> of a special tool
> >>isn't cost effective, that a commercial tool is
> cost prohibitive, or
> >>perhaps that a tool designed to solve some
> particular problem just does
> >>not exist.
> >>
> >>I was wondering if list members might share (the
> concept, not
> >>necessarily the tool) examples of innovative uses
> of general purpose
> >>computing tools to solve problems that they've
> either used or seen
> >>used.
> >>
> >>To start off, I'll volunteer the use of an Excel
> spreadsheet to
> >>recursively calculate the DC drop on a PCB from
> the VRM to the core
> >>power pins of a CPU packaged in a BGA package
> accounting for PCB
> >>cutouts, swiss-cheesing effects of anti-vias etc.
> There have recently
> >>become available elegant commercial tools that
> very accurately deal with
> >>this problem, however, in the past the problem of
> determining and
> >>visualizing these distributed voltage drops
> accurately (or even
> >>inaccurately) has been problematic.
> >>
> >>One other example, although not strictly SI
> related, is a shareware
> >>application a friend of mine developed called
> MultiNEC. Based on the
> >>Excel spreadsheet and utilizing the VB macro
> capability of that tool, it
> >>performs pre and post processing functions for NEC
> (Numerical
> >>Electromagnetic Code) simulations. It allows
> antenna geometries to be
> >>defined and then it generates the appropriate
> input decks for the
> >>simulator. It also analyzes and graphically plots
> the results from the
> >>NEC solve engine. Interface from the spreadsheet
> to the NEC simulator is
> >>seamless. There are many other capabilities
> integrated as well which all
> >>depend on the spreadsheet framework.
> >>
> >>I for one, would be interested in learning of
> other interesting
> >>applications of general purpose computing tools
> that engineers have come
> >>up with to deal with SI and other engineering
> problems. If anyone
> >>actually wants to share a particular tool that
> would
=== message truncated ===
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