Re: [SI-LIST] : Definition of Hi-Speed (UC)

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From: Scott McMorrow (scott@vasthorizons.com)
Date: Tue Nov 02 1999 - 05:34:24 PST


Andy,

I agree with you and would add the following:

Even if a net is low speed, such as a reset might
be by virtue of it's driving edge rate and frequency,
it still might end up being a high speed net by virtue
of being coupled into one. I have seen more system
problems due to crosstalk induced noise in resets
and quasi-static nets with weak pullups.

In my world, everything requires consideration of
being "high speed" unless proven otherwise.

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

"Ingraham, Andrew" wrote:

> >The starting clock frequency for high speed is F > 200 MHz/L, where L is > the > >longest length of the board, in inches. > > If I were you, I would not be tempted to entertain ANY frequency as the > onset of "high speed", no matter how many caveats you attach to it. > > Consider a system reset signal. Its frequency? Might be 1 cycle/year > (0.00000003 Hz) or lower. Is it in the realm of "high speed"? You bet! If > it rings like crazy and overshoots the dickens out of everything it touches, > it doesn't matter how many times a second you wiggle it. > > Andy > > **** 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 ****


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