[SI-LIST] Re: risetime effects of plane breaks
- From: Chris Cheng <Chris.Cheng@xxxxxxxxxxxx>
- To:
- Date: Fri, 14 Jan 2005 15:51:01 -0800
I would agree it will be worst but I am curious by how much.
This is by no means scientific nor an indication of one way or the other but
I have done quiet a few systems with relatively highspeed single ended
signals (DDR, CPU FSB) striplines crossing cut planes (not by my own
choice). And they seem to pass EMI,ESD and SI quite ok. I am genuinely
interested in a qualitative way of saying when I can get away with it and
when I can not. I have seen people in design reviews saying it will never
work but no one can provide data. That's why I ping all these replies. So
far I have not seen the data to say I should not do it but I am concern.
Everyone is repeating the same theme which is don't do it on microstrip
which I think is too obvious. And I truely believe in the 4 layer case like
Ahmad's example there should be a point made to investigate using stripline
over cut planes as an alternative to going 6 layers.
-----Original Message-----
From: Doug Smith [mailto:doug@xxxxxxxxxx]
Sent: Friday, January 14, 2005 3:34 PM
To: Chris.Cheng@xxxxxxxxxxxx
Cc: 'SI-List '
Subject: Re: [SI-LIST] Re: risetime effects of plane breaks
Hi Chris,
I believe the EMI will get worst. I nominate you to build the
experiment to generate some numbers!
Doug
Chris Cheng wrote:
> Thanks Charles,
> However, when you say it get worst, is it for the stripline case or
> microstrip like Doug did ? In the later case, we seem to agree no one will
> or should do it in real life. Are saying the EMI still get worst in
> stripline case with a solid ground on one side ?
>
--
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