Lee Ritchey's latest,
"Right the First Time: A Practical Handbook on High Speed PCB and System
Design"

is available FREE at this link:
http://www.thehighspeeddesignbook.com/


surfin' the learnin' curve,
jack


.
On Thu, Apr 22, 2010 at 2:04 PM, Brooks, Bill <[log in to unmask]> wrote:

>  Toby,
>
>
>
> Point well taken. A very good presentation was done on the affects of short
> rise time in slowly clocked digital boards. I believe Rick Hartley did that
> one for us here in San Diego a number of years ago.
>
> He pointed out that the IC manufacturers were using something called ‘die
> shrink’ as a technique to get more chips on a silicon wafer… which had the
> result of increasing the rise time of the digital signal’s transition from a
> zero to a one… this equivalent frequency of the transition was like in the
> GHz and the boards that were used to functioning with much slower equivalent
> circuits were now failing because of GHz signals being affected by the trace
> length being much too long or un terminated with pull up or pull down
> resistors to avoid ringing of the signal… Old boards that worked for years
> for the military were now failing with the ‘same’ exact parts because they
> really were not the same. They had changed internally…
>
> He gave us some pointers on design techniques to keep traces under 6 inches
> long and to make sure the return currents had a path directly under the
> signal thru a ground plane that was as close as possible to the signal… no
> impedance matching was talked about at that time…Adding terminating
> resistors or making sure the IC’s had them built in was talked about…  and
> the EMI/EMC suppression techniques were discussed as well I believe…
>
>
>
> Rick Hartley gave a very good workshop. Lee Richey of the Speeding Edge
> also is a good source for information on this subject and I believe Doug
> Brooks at UltraCad has some articles along those lines as well.
>
>
>
> Best regards,
>
> *Bill Brooks* | *Datron World Communications, Inc.**
> *PCB Designer/Engineer | Office: 760-602-7004| Fax: 760-597-3777 |
> [log in to unmask]
> 1808 Aston Avenue, Suite 230, Carlsbad, CA 92008 | www.dtwc.com
>
> *Performance You Require. Value You ExpectTM*
>  ------------------------------
>

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