Re: [SI-LIST] : Regarding plane splits

About this list Date view Thread view Subject view Author view

From: Mike LaBonte (mlabonte@hhnetwk.com)
Date: Tue Jan 02 2001 - 05:36:58 PST


Dennis,

Your stackups have 5 and 4 signal layers, respectively. When you say
you are using the same Gerber files, doesn't that mean the layer routes
are the same, with only the via padstacks changing? How is the "extra"
signal layer used?

Mike LaBonte

Dennis Yarak wrote:
>
> I haven't been following threads recently (too busy) but I do have a mildly
> interesting result to report in re: split planes.
>
> After discussions with our EMI experts we decided to do two different stack
> ups with the same gerber files. This is a 10 layer/50 ohm board with
> s-g-s-s-g-pslit-psplit-s-g-s, and the alternative was
> s-g-s-psplit-g-psplit-s-g-s.
>
> The first stack optimized for signal return path (only one signal layer sees
> the power split, and layer 8 was routed carefully) while the second
> optimized for VDD decoupling to ground.
>
> Even though this was as controlled an experiment for EMI as we could do, the
> specifics of the situation determine whether the result would be applicable
> in general. We didn't have the luxury of trying to reroute layer 3 to be
> better behaved across the new plane splits it sees in the alternate stack,
> for example.
>
> We found the first stack was a few dB better pretty much across the board.
>
> Dennis Yarak
>
> **** To unsubscribe from si-list or si-list-digest: send e-mail to
> majordomo@silab.eng.sun.com. In the BODY of message put: UNSUBSCRIBE
> si-list or UNSUBSCRIBE si-list-digest, for more help, put HELP.
> si-list archives are accessible at http://www.qsl.net/wb6tpu
> ****

**** To unsubscribe from si-list or si-list-digest: send e-mail to
majordomo@silab.eng.sun.com. In the BODY of message put: UNSUBSCRIBE
si-list or UNSUBSCRIBE si-list-digest, for more help, put HELP.
si-list archives are accessible at http://www.qsl.net/wb6tpu
****


About this list Date view Thread view Subject view Author view

This archive was generated by hypermail 2b29 : Tue May 08 2001 - 14:30:31 PDT