Thanks and regards.
- If one do not ask, he will never know -
Scott McMorrow wrote:
> Allen,
>
> Trace meanders will couple from edge to edge across the
> meander. This will cause an effective reduction of the
> characteristic impedance of the trace, unless the meanders
> are spaced quite wide. If you are not currently using them
> you should be using meander spacing that is 2X or 3X of the
> trace width for Rambus tracks. This should be equivalent to
> about a 20 to 30 mil edge to edge seperation of the meander
> tracks.
>
> regards,
>
> scott
>
> --
> Scott McMorrow
> Principal Engineer
> SiQual, Signal Quality Engineering
> 18735 SW Boones Ferry Road
> Tualatin, OR 97062-3090
> (503) 885-1231
> http://www.siqual.com
>
> Allen Wang wrote:
>
> > Dear all:
> >
> > We are designing a Rambus related product which requires the PCB to
> > maintain
> > 28 Ohm +/- 10% trace impedance.
> > However, what we have found that a straight line trace will get a higher
> > impedance (through TDR, 1 Ohm or more) than
> > a trace with many turns on it. We know a turn on the trace will change
> > the
> > impedance. However, is it the root cause
> > that make our trace impedance not consistent?
> >
> > Two traces are on the same layer, with the same trace width.
> >
> >
> > +---------------------------------------------------------------------------
> > ------------------------------------+
> > Straight line
> >
> > +-----------+ +------+ +---- \\\\ -----+
> > +------------------------+
> > | | | | | |
> > | | | | | |
> > +-----+ +----+ +---+
> > line with turns
> >
> > Allen
> >
> > **** To unsubscribe from si-list: send e-mail to [email protected]. In the BODY of message put: UNSUBSCRIBE si-list, for more help, put HELP. si-list archives are accessible at http://www.qsl.net/wb6tpu/si-list ****
>
> --
> Scott McMorrow
> Principal Engineer
> SiQual, Signal Quality Engineering
> 18735 SW Boones Ferry Road
> Tualatin, OR 97062-3090
> (503) 885-1231
> http://www.siqual.com
**** To unsubscribe from si-list: send e-mail to [email protected]. In the BODY of message put: UNSUBSCRIBE si-list, for more help, put HELP. si-list archives are accessible at http://www.qsl.net/wb6tpu/si-list ****