Re: [SI-LIST] : About multilayer Board

Dr. Edward P. Sayre (esayre@nesa.com)
Thu, 04 Dec 1997 13:58:19 -0500

Sounds like your board planes have been over-etched. Look at the the
perforation of the power and ground planes due to the anti-pads for vias
and plated through holes. If the copper web between the anti-pads are not
connected with 10-15 mils of copper, you will have significant inductance
associated with the plane and resulting EMI problems.

Sincerely,

ed sayre

At 06:53 PM 12/4/97 +0900, you wrote:
>Does anyone help on the effect of EMI suppression owing to the difference
>of copper thickness which is located on the inner layer of multi_layer
>board ?
>(This layer is used for GROUND or POWER plane.)
>
>
>Which is better the thickness become thick or thin ?
>
>And what is the reason why ?
>
>Thanks in advance.
>
>Best Regards.
>-------------------------------------------------------------
>Takashi Yanagimoto
>
>Ricoh Company Ltd.
>Tokyo Japan
>
>Email:yanasan@den.rp.ricoh.co.jp
>--------------------------------------------------------
>
>
>
>

+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~+
| NORTH EAST SYSTEMS ASSOCIATES, INC. |
| ------------------------------------- |
| "High Performance Engineering & Design" |
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~+
| Dr. Ed Sayre e-mail: esayre@nesa.com |
| NESA, Inc. http://www.nesa.com/ |
| 636 Great Road Tel +1.508.897-8787 |
| Stow, MA 01775 USA Fax +1.508.897-5359 |
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~+