[SI-LIST] : Different board vendors different impedances

Katie Rothstein (Katie_Rothstein@notes.teradyne.com)
Wed, 24 Mar 1999 10:27:11 -0500

Laurence,
Just a quick thought about your question. Different board vendors have
different processing capabilities (line width, total board thickness, board
size, etc.) This could be why some board shops can meet your required
impedances and some cannot. I'm not sure exactly what you are asking about the
different calculations, but many board houses have impedance calculation tools
that take empiricle data to help make corrections for their own processes.
-Katie

>>cut

ObContent: Has anyone noticed how different board vendors use different
calculations to get the same controlled impedance on the same board?
Some vendors will claim that it's impossible to meet impedance
requirements that other vendors can easily handle. Perhaps they are not
using the same materials, even though we specify FR4 and copper weight.
If you respond to this Content, please change the subject to something
more meaningful.

Regards,
-- Laurence

**** To unsubscribe from si-list: send e-mail to majordomo@silab.eng.sun.com. 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 ****

**** To unsubscribe from si-list: send e-mail to majordomo@silab.eng.sun.com. 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 ****