[SI-LIST] Re: Decoupling capacitors


Thanks Scott! I knew I shouldn't be doing math on a holiday......
(It just goes to show that as long as you are consistant with
your errors they all cancel out in the end :)

-Ray


Scott McMorrow wrote:
> 
> >
> >
> >For  example, say you are interested in effects up to 1 GHz on an
> >FR-4 board. The equivalent wavelength then would be (3e8/1000MHz)/sqrt(4)
> >or 150 cm.  1/10 of 150cm is 15 cm, so on a board whose size is say
> >300cm x 300cm you would ideally want a mesh of about 20x20 for maximum
> >accuracy. (if I haven't messed up the math :)
> >
> >
> >
> Ray,  that should be 150 mm, not 150 cm.  The 1/10 wavelength mesh would
> be 15 mm per square, or 590 mils per square.  So for a 300 mm x 300 mm
> (about 12 in x 12 in) board the ideal mesh for 1 GHz bandwidth would be
> 20 x 20.
> 
> The result is still the same. ( A 300cm x 300cm board would be pretty
> darn big!)
> 
> best regards,
> 
> scott
> 
> --
> Scott McMorrow
> Teraspeed Consulting Group LLC
> 2926 SE Yamhill St.
> Portland, OR 97214
> (503) 239-5536
> http://www.teraspeed.com
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