Cool. Traces are short, less than 2.5" max, getting shorter as I eliminate
resistors. :-)
Rise time is large, nominally it is 2 nsec.
Thanks for the vote
-----Original Message-----
From: Jon Elson [mailto:[EMAIL PROTECTED]]
Sent: Monday, August 06, 2001 4:08 PM
To: Protel EDA Forum
Subject: Re: [PEDA] 5/5 Manufacturing Issues
Tim Hutcheson wrote:
> Hi, Steve. This design is source terminated, that is, it absorbs the
> reflections at the source, which is 50 ohms. The resistors only match any
> residual difference between the source and the line impedance. So if I
can
> get that close to zero, they go away. I'm hoping someone will say that at
> 133mhz, the process variations won't matter to much for short lines (which
> get a lot shorter as I eliminate the resistors - it really tightens up).
It depends on your tolerance for reflections. If the lines are quite short,
just
a couple of inches, then it should work well. You are not going to get any
closer than 10% or so, from batch to batch. But, a 10% mismatch will not
produce large reflections, especially if things are lossy. What are the
rise/fall
times? Unless they are in the ps range, you should have no problem.
Jon
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* To post a message: mailto:[EMAIL PROTECTED]
*
* To leave this list visit:
* http://www.techservinc.com/protelusers/leave.html
* - or email -
* mailto:[EMAIL PROTECTED]?body=leave%20proteledaforum
*
* Contact the list manager:
* mailto:[EMAIL PROTECTED]
*
* Browse or Search previous postings:
* http://www.mail-archive.com/[email protected]
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
