[SI-LIST] Re: Thick vs. thin diff. pairs
- From: David Instone <dave.instone@xxxxxxxxxx>
- To: Mark_Burford@xxxxxxxxxxx
- Date: Mon, 20 Nov 2006 16:49:09 +0000
Mark,
One plus point for wide traces is that the etching tolerance, +/- 1 mil
on a 10 mil trace has less effect than +/- 1 mil on a 4 mil trace, same
goes for the spacing between the pairs.
Dave Instone
Oxford Semiconductor Ltd
25 Milton Park
Abingdon
Oxon ox14 4sh
UK
www.oxsemi.com
+44 (0)1235 824963
Mark Burford wrote:
> Dear all,
> I would like to ask opinions, on the merits and disadvantages of using
> wide or narrow microstrip lines.
>
> >From where I am sitting it looks like narrow microstrip diff. pairs have
> it won hands down.
>
>
>
> Thick lines:
>
> More area...which gives more dielectric loss as dielectric loss over
> takes skin effect losses at higher frequencies.
>
> More S11 because any corner on the line will give a greater area and
> more capacitance.
>
> Thicker substrates to keep the impedance at the right value.
>
> As thicker microstrip lines go round a bend, the inter-pair skew will be
> more than for two narrow lines.
>
> There is also the possibility of increased EMI from thicker substrates
> (been reading antenna design books).
>
>
>
> So please someone tell me why should we use thicker lines? And also
> please could someone tell me the trip ups of HDI (high density
> interconnect) such as how small can one realistically go with back plane
> and inter-chip routing?
>
>
>
> Thanks
>
> Mark
>
>
>
>
>
>
>
>
> ------------------------------------------------------------------
> 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 FAQ wiki page is located at:
> http://si-list.org/wiki/wiki.pl?Si-List_FAQ
>
> List technical documents are available at:
> http://www.si-list.org
>
> 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 FAQ wiki page is located at:
http://si-list.org/wiki/wiki.pl?Si-List_FAQ
List technical documents are available at:
http://www.si-list.org
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
Other related posts:
