[SI-LIST] Re: Impedance Controlled Board Production Vs Normal Board Production

  • From: Faraydon Pakbaz <pakbazf@xxxxxxxxxx>
  • To: "Mikhail Matusov" <matusov@xxxxxxxxxxxx>
  • Date: Thu, 5 Jan 2012 11:18:20 -0500

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




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  |[SI-LIST] Re: Impedance Controlled Board Production Vs Normal Board 
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  |si-list-bounce@xxxxxxxxxxxxx                                                 
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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
>>
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>
>
> --
> Steve Weir
> IPBLOX, LLC
> 150 N. Center St. #211
> Reno, NV  89501
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