[SI-LIST] Re: PCB Stackup

From: "David Hoover" <dhoovy@xxxxxxxxxxxxx>
To: <Steve.Zimmer@xxxxxxxxxxxxxxx>, <sengeman@xxxxxxxxxxxx>,<si-list@xxxxxxxxxxxxx>
Date: Sat, 1 Jun 2002 17:36:51 -0700
Like Steve said, the registration is the main driving factor. Each material
core
has it's own set of front-to-back registration tolerances. If two different
cores
were used (with prepreg in between) then two sets of tolerances may now
align
the broadside coupled traces. If the linewidths were fairly small, that
double set of
tolerances could greatly impact the differential impedance findings.

Cheers,

David Hoover
Staff Applications Engineer
Multek (based in the SF Area)
----- Original Message -----
From: "Zimmer, Steve" <Steve.Zimmer@xxxxxxxxxxxxxxx>
To: <sengeman@xxxxxxxxxxxx>; <si-list@xxxxxxxxxxxxx>
Sent: Thursday, May 30, 2002 10:09 AM
Subject: [SI-LIST] Re: PCB Stackup


> Generally, the Broadside coupled traces are on opposite sides of a core.
> This helps to ensure that the two traces remain directly above/below each
> other.
>
> Having prepreg between these cores could result in some registration skew
> which may yield traces that are not directly on top/below each other.
> Depending on the line lengths, widths registration and impedance tolerance
> this may or may not pose a problem. I think that this is the risk.
>
> -----Original Message-----
> From: sengeman@xxxxxxxxxxxx [mailto:sengeman@xxxxxxxxxxxx]
> Sent: Thursday, May 30, 2002 12:53 PM
> To: si-list@xxxxxxxxxxxxx
> Cc: sengeman@xxxxxxxxxxxx
> Subject: [SI-LIST] PCB Stackup
>
>
> Greetings all,
> A general question:
> without geting into specifics of dimensions and dielectric constants, is
> there a consensus regarding positioning of broadside coupled layers in a
> PCB?
> Specifically, how important is it to keep the broadside layers on
> opposite sides of a core vs. having prepreg between the two layers?
> Thanks,
> Steve
>
> ------------------------------------------------------------------
> 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
>
>
>
> ------------------------------------------------------------------
> 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
>
>

------------------------------------------------------------------
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
[SI-LIST] Re: PCB Stackup

Other related posts:
