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Date: | Tue, 17 Sep 1996 11:29:25 -0700 |
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> We have been using vias without thermal pads for some time now, and have
> had no problem at all. To my knowledge our fab vendors did not even notice
> the difference.
>
> Due to our heavy use of smt, virtually all our boards are 100% or 99.99%
> surface mount, removing the thermal pad and connecting our vias directly to
> the plane improved the emi-esd characteristics of our boards. It has been
> a good deal all around.
>
> In addition to this, we have also reduced the size of our anti pads. We
> were having problems with signal quality due largely to "impedance bumps"
> which would occur when a trace passed a pad with a large anti pad. This
> was because as the trace would pass over the anti pad, it would suddenly
> not have a ground layer to associate to. To cure this problem, we have
> reduced our anti pads to a size where when traces pass by at minimum distance,
> there is adaquate coverage by the associated layer.
>
Ditto... This is exactly what we have done for the last 3-5 years, and have
gotten the same results and findings. Great work! and good wording.
Mitch Morey
Sr. PCB Designer
TRW, Inc.
Redondo Beach, CA 90278
Phone: (310)814-5765
Fax: (310)812-4949
EMAIL: [log in to unmask]
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PCB layout is like fine art. You have to DIE to be famous!
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