Hi Consider that microvolts matter on the EFC. Unless you have a separate return for the oven current it’s going to be tough to keep everything separate. One might ask “why no separate return”. Well when you design one in, and then go look at people’s layouts - you might as well not have designed it in …..
Bob On Oct 30, 2013, at 8:37 PM, John C. Westmoreland, P.E. <j...@westmorelandengineering.com> wrote: > Graham and Time Nuts, > > (thanks for the answers.) > > I have another question - I am looking at a part from MTI. I wanted to use > one of their 3.3V parts. They are telling me to use the 12V part because > the 3.3V part can have an issue with ground loops due to the higher current > requirements at that voltage for the oven. > > Have any of you experienced this? Makes me wonder a little why they offer > the 3.3V part. It would seem good layout can control any possibility of > ground loops becoming a problem. > > Thanks and Regards, > John W./AJ6BC > > > > > On Wed, Oct 30, 2013 at 6:54 AM, Graham / KE9H <time...@austin.rr.com>wrote: > >> John: >> >> All SMT OCXO's will either have a recommended PCB footprint in the spec >> sheet >> or will refer you to a recommended footprint in another document. >> >> Some don't care about a ground plane under the part, some require it >> with no crossing signals, some require an open thermal hole underneath >> the oven. I have seen all three cases. As usual, it is suggested that you >> read the [] manual. >> >> Best regards, >> --- Graham / KE9H >> >> == >> >> >> >> On 10/29/2013 9:18 PM, John C. Westmoreland, P.E. wrote: >> >>> Hello, >>> >>> I was wondering if I could get some recommendations on surface mount >>> OCXO's >>> vs. the traditional through hole. >>> >>> I was also wondering on the board layout - if you found it necessary to >>> leave a thermal moat so to speak - and what worked best. Maybe the OCXO >>> has an internal air barrier that maybe would make this unnecessary - not >>> sure. >>> >>> Your input and experience appreciated. >>> >>> Thanks, >>> John Westmoreland >>> ______________________________**_________________ >>> time-nuts mailing list -- time-nuts@febo.com >>> To unsubscribe, go to https://www.febo.com/cgi-bin/** >>> mailman/listinfo/time-nuts<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> >>> and follow the instructions there. >>> >>> >> ______________________________**_________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/** >> mailman/listinfo/time-nuts<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> >> and follow the instructions there. >> > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
