[SI-LIST] Re: IPC standard for impedance coupons

I second that.  The best approach is to build the impedance test traces into 
the PCB itself.  That way, the never get lost, the always represent the PCB 
they are on.

You can test them any time you have a concern.

Lee

--------------------------------------------------
From: "Scuteri, Jeremy" <Jeremy.Scuteri@xxxxxxxxxx>
Sent: Thursday, December 09, 2010 10:57 AM
To: "Joel Brown" <joel@xxxxxxxxxx>; <si-list@xxxxxxxxxxxxx>
Subject: [SI-LIST] Re: IPC standard for impedance coupons

> If at all possible, it is best to put test traces on the actual board. 
> This will guarantee that your test traces accurately represent what is on 
> your board.  I have heard about cases where special care has been taken 
> for coupons, so the board house looks good and then the boards were run on 
> a different lot.
>
> Jeremy Scuteri
> Product Engineer
> Analog Devices Inc.
>
> -----Original Message-----
> From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] 
> On Behalf Of Joel Brown
> Sent: Thursday, December 09, 2010 1:46 PM
> To: si-list@xxxxxxxxxxxxx
> Subject: [SI-LIST] IPC standard for impedance coupons
>
> Does anybody know what the applicable IPC spec is for impedance testing 
> and coupons?
> We have been referencing IPC-2221 on our PCB drawings but I could not find 
> anything on impedance coupons in this standard.
>
> It seems like IPC-2141A might be what I am looking for but I don't have a 
> copy but have ordered it.
>
> Also how closely should a coupon match the actual board? If there are 
> controlled impedance traces that transition between various layers, should 
> the coupon include the same layer structure including vias, or is there a 
> separate impedance test done for each layer?
>
>
>
> Thanks - Joel
>
>
>
>
>
>
>
> ------------------------------------------------------------------
> 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:
> http://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:
>                http://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:
> http://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:
> http://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:
http://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:     
                http://www.freelists.org/archives/si-list
 
Old (prior to June 6, 2001) list archives are viewable at:
                http://www.qsl.net/wb6tpu

Other related posts: