Out of the replies, I conclude that the ground plane is the best solution. I
agree with this. However what is you have a 2 sided board. Is shielding then
improving for traces that have to carry very low analog signals to high
impedance inputs (e.g. FET OP Amp inputs)? Or, is in this case, a clearance
of 2 times the linewidth better.

What is than better in topology? Connecting to ground every 1" or leave as
an open end and connect at the driver side. What clearances and linewidths
should I use for the shielding trace.

Also I noticed an opinion about guard bands mirrors Jeffrey's. Can anybody
tell me more about this.

best regards,

Joachim Verhagen [mailto:[log in to unmask]]
consulting engineer, EASEurope B.V. [http://www.easeurope.com]
Goorseweg 5, 7475 BB Markelo, Netherlands, tel. +31 (0)547 - 367 347



> -----Original Message-----
> From: DesignerCouncil [mailto:[log in to unmask]]On Behalf Of
> Hawes, Adam
> Sent: Tuesday, July 27, 1999 10:08
> To: [log in to unmask]
> Subject: [DC] Ground Shield Tracks
>
>
>         I feel sure this is probably an issue for a lot of PCB
> designers......
>
>         Recently, I have come across an increasing number of engineers who
> wish to have certain tracks on multilayer PCB's shielded by ground traces
> running adjacently. It seems to be a case of jumping on the
> bandwagon to me
> because we never used to do this until about 12 months ago.
>
>         I was under the impression that ground tracks only served a useful
> purpose on 1or 2 layer boards and that on a multilayer they were
> essentially
> a waste of space as most of the capacitive coupling would be
> straight to the
> ground plane.
>
>         I don't like to tell the engineers their jobs obviously so can
> anybody put forward their views so I have a more solid argument!
>
>         Thanks all,
>
> Adam Hawes
> PCB Design Eng.
> GenRad Ltd.
>
> Tel: 0161  491 9290
> Fax: 0161 491 9106
>