I definitely agree with Thomas. This is a very generic question because there are a lot of parameters = affecting the design. Time to market, specification complexity & changes down the road play a = major role. Sometimes we have to get the first revision out just to show = a piece of Hardware. For our company it varies and we generally get the production build at = the rev2 phase of the design. Regards, Ruturaj Pathak Sr. HW Design Engineer EFI Corporation -----Original Message----- From: Jackson, T L [mailto:t.l.jackson@xxxxxxxx] Sent: Thursday, November 07, 2002 1:32 PM To: 'breams@xxxxxxxxxxxxxx'; 'Si-List' (E-mail) Subject: [SI-LIST] Re: Off Topic Question In my experience, If one has a firm description of what the design is supposed to do and if one is willing to put the effort into serious modeling and design = checks before starting fabrication and assembly, one can go to production on the first layout. This has the disadvantage = of taking the longest time until there is something tangible that = Management and/or Marketing can show to potential customers. In the real world, someone has to make the tradeoff between the amount = of modeling performed before fabrication versus the cost of debugging and respinning a design. Somewhere between the two extreme of "model = everything in excruciating detail" and repeated "Build and Test" is the lowest = cost, fastest path to production. The hard part is figuring out where this = point is for a given design, staff, toolset, company, etc. All this assumes = one is not trying to hit a moving target, i.e. the functions, performance, = cost target, etc. are not changing during development. Personally, I have gotten it right on the first time more than once and never took more than two. TJ Thomas L. Jackson, PE Senior Staff System Engineer L1-50, Remote Sensing Systems Engineering Missiles and Space Operations Lockheed Martin Space Systems Company telephone: (408) 742-2013 facsimile: (408) 742-7701 location: B149/E2 -----Original Message----- From: Bill Reams [mailto:breams@xxxxxxxxxxxxxx] Sent: Thursday, November 07, 2002 1:01 PM To: 'Si-List' (E-mail) Subject: [SI-LIST] Off Topic Question Ladies and Gentlemen, I have a question that is off topic for this list. However, as we all = =3D work at companies ranging from medium tech to very high tech, this =3D seemed a good source for a non-scientific poll. For your "typical" projects, how many circuit board revisions does it = =3D take to go from the block diagram stage to full production release? I know that in the perfect world, everyone would answer "One board, my = =3D first prototype is always perfect." But we've probably all seen the =3D project where we're sent off to design a left-handed widget and =3D eventually deliver the flux capacitor that they really wanted - but only = =3D after a large number of revisions and redesigns because they couldn't = =3D figure out how to ask for what they wanted. What I'm interested in is = =3D not the extreme revision numbers, but the typical number of revisions = =3D for typical projects. And please do include all revisions for DFM, DFT, = =3D EMC/EMI related modifications. Thanks for your responses. Bill _______________________________________ | | | Bill Reams - Sr. Hardware Engineer | | 512-928-7201 (direct) | | 512-349-0300 (Main) | | breams@xxxxxxxxxxxxxx (e-mail) | |______________________________________| ------------------------------------------------------------------ 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 archives are viewable at: =20 //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages=20 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 archives are viewable at: =20 //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages=20 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 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