[SI-LIST] Re: 50 ohm and 130 ohm on the same board

S A Prasad:

You could use a low dielectric material on exterior surfaces such as =
Polyimide (3.1~3.3) this will help. However, 50 ohm trace widths would =
be around 1.27 mm (0.050") which is a size good for RF circuits for 0805 =
components. Alternatively, Void out the top two layers under the 130 ohm =
layers so the height above the plane is taller. The limititing factor on =
this is the overall board thickness.
Hope that was useful

Steve Salkow=20
Lockheed Martin=20
3200 Zanker Road=20
San Jose, CA 95134=20
(408) 473-4058 (san Jose)=20
(408) 742-4162 (Sunnyvale)=20
steven.salkow@xxxxxxxx=20
salkow@xxxxxxxxxxxx=20
(925) 462-1075 Home=20
(925-) 487-5946 Cell=20
(408) 468-7271 Numeric Pager=20

=20


-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] =
On Behalf Of saprasad
Sent: Wednesday, June 02, 2004 8:09 AM
To: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: 50 ohm and 130 ohm on the same board


Hello All,

I have a board with 2 sets of signal, the first set of nets need to be =
at 50ohm characteristic impedance and the other at 130ohm (single =
ended). This is not practically possible due to manufacturing =
constrains.

Can you suggest me some technique so i can archive this on the board.

Board details are as fallows:
No. of Layers: 6
Stackup: top, ground, signal, signal, power, bottom
Board thickness is 1.6mm

Regards,
S A Prasad

+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
This e-mail is intended for the use of the individual or entity named =
above and may contain information that is confidential and privileged. =
If you are not the intended recipient, you are hereby notified that any =
dissemination, distribution or copying of this e-mail is strictly =
prohibited.If you have received this e-mail in error, please notify us =
immediately at prasadsa@xxxxxxxxxx and destroy the original message. =
While this e-mail and any attachments have been scanned for common =
computer viruses and found to be virus free, we recommend you also =
perform your own virus checking processes before opening any =
attachments.
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

----- Original Message -----
From: "sghsu55" <sghsu55@xxxxxxxxxxxx>
To: <John@xxxxxxxxxxxx>; <si-list@xxxxxxxxxxxxx>
Sent: Wednesday, June 02, 2004 2:54 PM
Subject: [SI-LIST] Re: Power plane resonace for multi-plane issues


>
> John,
>
> We have ever conducted lots of simulation and
> measurement for the
> similiar PDS structure as you described. In our
> experiences, SpeedXP
> can got quite accurate results with VNA measurement. Especially, the
> prediction of resonance frequency of PDS plane pair.
> The results of
> SpeedXP were slightly greater than measured as well
> may come from the
> fringing effect in the edge of plane. I don't have
> sufficient
> information to understand your case and simulation
> setting. However,
> in my opinion, I don't think that the overlap between
> VCCP and VCC3_3
> is a good design.
>
> Best regards,
>
> Sogo Hsu Ph. D.
>
> Foxconn
>
>  --- John Lin (aL=A1=A6A=A1P=A1=D1) <John@xxxxxxxxxxxx> =
ao=A2XTR=A1=B1!G>
> Dear all SI gurus,
> > one question regarding Power plane resonance.
> > Currently, I use SpeedXP from Sigrity for simulating
> > power plane resonance.
> > The set up is that
> >            TOP layer :       VCCP
> > -----  on top layer,
> >            2nd layer  :      GND, VCC3_3  --
> > partially overlap both plane  on the second layer
> >            3rd layer :         GND
> >           ....
> >            BOT layer:       VCCP                  --
> > on bottom layer
> >
> >  I inject a current pulse into VCCP at a node on the
> > top layer. With Fourier transfer for  voltage and
> > current, and got a plot of plane impedance.   My VNA
> > measurement shows a resonance at 50 Mhz, but the
> > simulation show 100Mhz.
> > I think the mismatch may be among , VCCP,VCC3_3, and
> > GND plane .  Shall I let VCC3_3 plane float or tie
> > it to somewhere?
> >
> > I know Cadence's PI tool need to specified each
> > overlapping plane pairs with correct voltage
> > difference for multi-plane issues.
> >
> > I don't know how to take care current injection
> > issues on Sigrity SpeedXP for multi-planes.
> >
> > Does somebody please kindly shed some light on it.
> >
> > Thanks,
> > John
> >
>
>
>
> -----------------------------------------------------------------
> =A1=B1Uan=A1Mo!I!IEmail3B3B|?!I
> =A1=B1K?O?U=A1MuYahoo!c_?=A1=C2=A1=D3?R||C
> http://tw.companion.yahoo.com/
> ------------------------------------------------------------------
> 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:=20
> http://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:=20
> http://www.freelists.org/archives/si-list
> or at our remote archives:=20
> 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: =
http://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:    =20
                http://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
 =20

------------------------------------------------------------------
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 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:     
                http://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: