Hi All, I think that this is a very important lesson for some new (and perhaps old) folks to be aware of. That being, do not assume that the application note that you have in front of you is passed down from the gods above, implemented in volume, checked over PVT or checked at all. Often times a healthy amount of skepticism can be a very valuable signal integrity tool, especially when 'blindly' copying someone's design, app note or not. In the same way that a model can only be trusted so far, one must perform due diligence to assess exactly how good an application note is. I am sure that many of the folks on this list have sent a kind email back to a chip manufacturer letting them know that their calculations, topologies, assumptions etc were less than accurate, dead wrong, or yes. However, before the flamefest erupts, there are a great number of vendors who do a fantastic job, generating app notes that are properly researched, consider variations in process, temp, V, other, are correct and extremely useful. My point is to review the data, question when you see something that doesn't seem quite right, find out if anyone including the vendor has followed it, and proceed when you believe everything appears correct. When push comes to shove, the engineer is responsible for the operation of the circuit and not the generator of the app note. The best ones I like are where a vendor is figuring timing and assumes best case timing in the setup case and worst case timing in the hold case or vice versa. Actual implementation is left as an exercise for the reader. Getting back to Mike's issue. Now that it sounds like things have been implemented, are you stuck with an ecl source or do you have the ability to rethink everything from scratch. This may make a difference in what the best way to solve this opportunity is. Please advise, best regards, Michael C. Greim MTS - Signal Integrity SONUS Networks Voice: +1 978 589 8336 Fax: +1 978 392 9118 email : mgreim@xxxxxxxxxxxx <mailto:mgreim@xxxxxxxxxxxx> Internet: www.sonusnetworks.com <http://www.sonusnetworks.com> The Voice of the New Public Network.(tm) The time is gone, the email's over Thought I'd something more to say And All this science they don't understand It's just my job six days a week -----Original Message----- From: Robison Michael R CNIN [mailto:Robison_M@xxxxxxxxxxxxxx] Sent: Monday, November 26, 2001 1:44 PM To: si-list@xxxxxxxxxxxxx Subject: [SI-LIST] replacing ECL ?? hello, we recently put together an ECL clock divider and phase shifter printed circuit board. the circuit was taken from a design application, which has since proven to be somewhat of a joke. the company rep stated that although they had published the app note, the circuit was theoretical and would probably not work at the advertised speed. hahaha. jokes on us. we have 576MHz coming onto the board, where it is divided down into a phase-locked 32MHz, 16MHz, and 2MHz signal clock. we plan on getting around gate- delay by using a digitally tuned phase shifter to shift divided pulses to sync with the 576MHz. i have heard that ECL is often a poor choice for designs today because of other newer technologies with better noise margins. could you please recommend a good technology to use, and note a source for information and acquisition? thank you, miker ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu