From: Charles Grasso ([email protected])
Date: Tue Jun 20 2000 - 23:30:55 PDT
Please explain "work". Does this mean lower crosstalk lower EMI??
----- Original Message -----
From: <[email protected]>
To: <[email protected]>
Sent: Tuesday, June 20, 2000 9:03 AM
> I have gotten numbers using xfx that indicate guard traces do work. More
> importantly, I have seen positive effects on real boards. It is not
important
> to via to ground every "X" intervals of distance. It is critical that the
> "guard traces" are grounded at the source and receiver. It is also
necessary
> for the guard traces to via whenever the signal does. For instance, if
you have
> a clock trace that vias from layer 1 to layer 4 and is routed as
> ground-signal-ground (GSG), the ground (guard) trace should via from layer
1 to
> layer 4 very closely.
>
>
> See below for some quick results. Compare numbers in bold for effects on
> crosstalk.
>
> Brandon Kemp
> EMC/SI Engineer
> Lexmark International, Inc.
>
>
>
> Trace width = 6 mils
> Edge to edge separation = 6 mils
> Height above ground plane = 7 mils
> Er = 4.5
>
> 1.
> S S
> ___ ___
> ___________________________GP
> Signals separated by 6 mil
>
>
> Configuration Name: SS_GP_7mil Conductors: 2
> #INTEGRAL solution#
> Conductor index: 0 name: $$GND$$
> Conductor index: 1 name: 1
> Conductor index: 2 name: 2
>
> i j Lij Cij Ze Zo Se So Fwdx Rvsx
> from to (nh/in) (pf/in) (ohms) (ohms) (ns/ft)(ns/ft) (s/s) (v/v)
> --------------------------------------------------------------------------
> 1 1 9.791 2.176 68.57 - 1.71 - - -
> 1 2 2.735 0.334 82.47 53.02 1.82 1.60 0.132 0.217
> 2 2 9.791 2.176 68.56 - 1.71 - - -
> ;
>
>
> 2.
> S S
> ___ ___
> _____________________________GP
> Signals separated by 18 mil
>
>
>
> Configuration Name: S_S_GP_7mil Conductors: 2
> #INTEGRAL solution#
> Conductor index: 0 name: $$GND$$
> Conductor index: 1 name: 1
> Conductor index: 2 name: 2
>
> i j Lij Cij Ze Zo Se So Fwdx Rvsx
> from to (nh/in) (pf/in) (ohms) (ohms) (ns/ft)(ns/ft) (s/s) (v/v)
> --------------------------------------------------------------------------
> 1 1 9.842 2.117 68.27 - 1.73 - - -
> 1 2 0.928 0.061 72.37 63.97 1.79 1.67 0.066 0.062
> 2 2 9.842 2.117 68.28 - 1.73 - - -
> ;
>
>
> 3.
> G S G S
> ___ ___ ___ ___
> _____________________________GP
> Signals separated by 18 mils, one trace routed GSG
>
>
> Configuration Name: GSGS_GP_7mil Conductors: 2
> #INTEGRAL solution#
> Conductor index: 0 name: $$GND$$
> Conductor index: 1 name: 1
> Conductor index: 2 name: 2
> XFX V6.5.0 Report 16 Jun 13:55 2000 Setup File =
> F:\bkemp\xfx\Scarecrow\Clocks\clks.xfx
>
>
> i j Lij Cij Ze Zo Se So Fwdx Rvsx
> from to (nh/in) (pf/in) (ohms) (ohms) (ns/ft)(ns/ft) (s/s) (v/v)
> --------------------------------------------------------------------------
> 1 1 8.206 2.253 60.35 - 1.63 - - -
> 1 2 0.237 0.022 61.51 59.18 1.65 1.62 0.019 0.019
> 2 2 8.928 2.184 63.94 - 1.68 - - -
> ;
>
>
> .xfx
> CONFIG SS_GP_7mil e: 1.00
> INTEGRAL
> DIELECTRIC e: 4.50 HORIZ_PLANE y: 0.0 7.0
> CONDUCTOR 1 RECTANGLE x: 0.0 6.0 y: 7.0 9.0
> CONDUCTOR 2 RECTANGLE x: 12.0 18.0 y: 7.0 9.0
> GROUND HORIZ_PLANE y: -1.5 0.0;
>
> CONFIG S_S_GP_7mil e: 1.00
> INTEGRAL
> DIELECTRIC e: 4.50 HORIZ_PLANE y: 0.0 7.0
> CONDUCTOR 1 RECTANGLE x: 0.0 6.0 y: 7.0 9.0
> CONDUCTOR 2 RECTANGLE x: 24.0 30.0 y: 7.0 9.0
> GROUND HORIZ_PLANE y: -1.5 0.0
> ;
>
> CONFIG GSGS_GP_7mil e: 1.00
> INTEGRAL
> DIELECTRIC e: 4.50 HORIZ_PLANE y: 0.0 7.0
> GROUND RECTANGLE x: -12.0 -6.0 y: 7.0 9.0
> CONDUCTOR 1 RECTANGLE x: 0.0 6.0 y: 7.0 9.0
> GROUND RECTANGLE x: 12.0 18.0 y: 7.0 9.0
> CONDUCTOR 2 RECTANGLE x: 24.0 30.0 y: 7.0 9.0
> GROUND HORIZ_PLANE y: -1.5 0.0
> ;
>
>
>
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