[SI-LIST] Re: Using general purpose computer tools to solve SI problems
- From: Alan Hilton-Nickel <alan@xxxxxxxxxxxxxxxxx>
- To: bmgman@xxxxxxxxxx
- Date: Wed, 29 Sep 2004 19:44:26 -0700
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 be great, but just
>>the general knowledge of what has been or can be done may provide the
>>impetus for others to develop their own applications.
>>
>>
>>-Ray Anderson
>>------------------------------------------------------------------
>>To unsubscribe from si-list:
>>si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>>
>>or to administer your membership from a web page, go to:
>>//www.freelists.org/webpage/si-list
>>
>>For help:
>>si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>>
>>List FAQ wiki page is located at:
>> http://si-list.org/wiki/wiki.pl?Si-List_FAQ
>>
>>List technical documents are available at:
>> http://www.si-list.org
>>
>>List archives are viewable at: =20
>> //www.freelists.org/archives/si-list
>>or at our remote archives:
>> http://groups.yahoo.com/group/si-list/messages
>>Old (prior to June 6, 2001) list archives are viewable at:
>> http://www.qsl.net/wb6tpu
>> =20
>>
>>
>>------------------------------------------------------------------
>>To unsubscribe from si-list:
>>si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>>
>>or to administer your membership from a web page, go to:
>>//www.freelists.org/webpage/si-list
>>
>>For help:
>>si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>>
>>List FAQ wiki page is located at:
>> http://si-list.org/wiki/wiki.pl?Si-List_FAQ
>>
>>List technical documents are available at:
>> http://www.si-list.org
>>
>>List archives are viewable at:
>> //www.freelists.org/archives/si-list
>>or at our remote archives:
>> http://groups.yahoo.com/group/si-list/messages
>>Old (prior to June 6, 2001) list archives are viewable at:
>> http://www.qsl.net/wb6tpu
>>
>>
>>
>>
>>
>
>
>------------------------------------------------------------------
>To unsubscribe from si-list:
>si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>
>or to administer your membership from a web page, go to:
>//www.freelists.org/webpage/si-list
>
>For help:
>si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>
>List FAQ wiki page is located at:
> http://si-list.org/wiki/wiki.pl?Si-List_FAQ
>
>List technical documents are available at:
> http://www.si-list.org
>
>List archives are viewable at:
> //www.freelists.org/archives/si-list
>or at our remote archives:
> http://groups.yahoo.com/group/si-list/messages
>Old (prior to June 6, 2001) list archives are viewable at:
> http://www.qsl.net/wb6tpu
>
>
>
>
>
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List FAQ wiki page is located at:
http://si-list.org/wiki/wiki.pl?Si-List_FAQ
List technical documents are available at:
http://www.si-list.org
List archives are viewable at:
//www.freelists.org/archives/si-list
or at our remote archives:
http://groups.yahoo.com/group/si-list/messages
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
Other related posts:
