Greeting Signal Integrity Experts; My apology if I am asking off target question with the impedance tolerance...but doesn't impedance of the board gets defined based on the "target impedance" of specific application (i.e ASIC) and its tolerance based on the worse case condition of current draw( and its variation) and the noise tolerance of specific sensitive circuit or Core in design? I mean with cost aside that experts discussed and I think it is extremely important, doesn't application dictates the tolerance? Regards; Don Pakbaz |------------> | From: | |------------> >--------------------------------------------------------------------------------------------------------------------------------------------------| |"Mikhail Matusov" <matusov@xxxxxxxxxxxx> | >--------------------------------------------------------------------------------------------------------------------------------------------------| |------------> | To: | |------------> >--------------------------------------------------------------------------------------------------------------------------------------------------| |<si-list@xxxxxxxxxxxxx> | >--------------------------------------------------------------------------------------------------------------------------------------------------| |------------> | Date: | |------------> >--------------------------------------------------------------------------------------------------------------------------------------------------| |01/05/2012 11:06 AM | >--------------------------------------------------------------------------------------------------------------------------------------------------| |------------> | Subject: | |------------> >--------------------------------------------------------------------------------------------------------------------------------------------------| |[SI-LIST] Re: Impedance Controlled Board Production Vs Normal Board Production | >--------------------------------------------------------------------------------------------------------------------------------------------------| |------------> | Sent by: | |------------> >--------------------------------------------------------------------------------------------------------------------------------------------------| |si-list-bounce@xxxxxxxxxxxxx | >--------------------------------------------------------------------------------------------------------------------------------------------------| I don't think those who responded understood the question correctly. I think the OP was asking whether some degree of impedance control can be achieved by precisely specifying the board's stackup, width of the traces, and process tolerances without explicitly asking the manufacturer to control impedance. For some applications it just boils down to the cost. If I, as a designer, know the process and materials used by the particular manufacturer well enough I should be able to specify the board in such a way that the impedance will end up in the right ballpark. In fact, I use this method for non-critical designs. ======================= Mikhail Matusov Senior Hardware Design Engineer Square Peg Communications Tel.: +1 (613) 271-0044 ext.231 Fax: +1 (613) 271-3007 http://www.squarepeg.ca ----- Original Message ----- From: "Loyer, Jeff" <jeff.loyer@xxxxxxxxx> To: <si-list@xxxxxxxxxxxxx> Sent: Thursday, January 05, 2012 10:22 AM Subject: [SI-LIST] Re: Impedance Controlled Board Production Vs Normal Board Production > Perhaps I'm the only one who is finding it ironic that, on a "Signal > Integrity" reflector list, "Impedance Controlled" isn't considered > "Normal". I haven't had the luxury of not specifying impedance control > since a small 33MHz PCI card design, many years ago. > > I'm afraid Jayasuryan that you won't find the answer you're looking for on > an e-mail thread, or it is going to be a long, drawn out, painful affair. > You have a lot of work to do to understand what impedance control is and > how it relates to signal integrity. I would recommend starting with the > books that have been listed many times on this list. You can also search > the archives for "impedance control" to find discussions about different > opinions on how much is enough. > > Good luck in the new year, > Jeff Loyer > > -----Original Message----- > From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] > On Behalf Of steve weir > Sent: Monday, January 02, 2012 6:23 AM > To: si-list@xxxxxxxxxxxxx > Subject: [SI-LIST] Re: Impedance Controlled Board Production Vs Normal > Board Production > > Suppose as you like. Hope as you might. What you don't contract is not > guaranteed. > > Steve. > On 1/2/2012 5:56 AM, Jayasuryan KG wrote: >> Dear Experts, >> >> >> >> Happy New Year!! >> >> >> >> I have question regarding the impedance controlled board production! >> Is there any special process to produce impedance controlled board >> >> rather than the normal production? >> >> >> >> Suppose if I go with normal production for a impedance controlled board >> (the design has been done to meet the impedance) what are the possible >> issues can happen? >> >> >> >> Looking for your immediate response. Thanks in advance. >> >> >> >> Best Regards, >> >> - Jayasuryan >> >> ------------------------------------------------------------------ >> 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 technical documents are available at: >> http://www.si-list.net >> >> List archives are viewable at: >> //www.freelists.org/archives/si-list >> >> Old (prior to June 6, 2001) list archives are viewable at: >> http://www.qsl.net/wb6tpu >> >> >> > > > -- > Steve Weir > IPBLOX, LLC > 150 N. Center St. #211 > Reno, NV 89501 > www.ipblox.com > > (775) 299-4236 Business > (866) 675-4630 Toll-free > (707) 780-1951 Fax > > All contents Copyright (c)2012 IPBLOX, LLC. All Rights Reserved. > This e-mail may contain confidential material. > If you are not the intended recipient, please destroy all records and > notify the sender. > > ------------------------------------------------------------------ > 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 technical documents are available at: > http://www.si-list.net > > List archives are viewable at: > //www.freelists.org/archives/si-list > > 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 technical documents are available at: > http://www.si-list.net > > List archives are viewable at: > //www.freelists.org/archives/si-list > > 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 technical documents are available at: http://www.si-list.net List archives are viewable at: //www.freelists.org/archives/si-list 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 technical documents are available at: http://www.si-list.net List archives are viewable at: //www.freelists.org/archives/si-list Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu