There is no "cleanup" PLL in the SG8002, the output spectrum looks like that of a cheap PLL-on-a-chip. I did not see any evidence of wide band spurs but the phase noise is terrible, as you would get when the VCO and it's tank components are on-chip, which is the only way they could achieve the price point.
My experience also shows that high level of radiated noise around the device (as when used inside a high power switching supply) causes it to malfunction, as if it was losing lock. In our applications, they have to be shielded. Didier Tim Shoppa <tsho...@gmail.com> wrote: >SG8002 is definitely a distributor programmable unit. > >It is a digital synthesizer in a can with no effort towards clean >output. > >PLL? They would not bother to put a cleanup PLL in the can for the >intended microprocessor application. > >Tim N3QE > >On 7/21/13, Didier Juges <shali...@gmail.com> wrote: >> I am familiar with the Epson Seiko SG8002 series and nowhere does it >say >> they are programmable. They are not user programmable for sure, only >the >> distributor has the tools to do it. The data sheet does not have any >> information that would be a hint that they are PLL's. >> >> Http://WWW.KO4BB.com/Timing/MicroprocessorCrystals.php >> >> Didier >> >> Hal Murray <hmur...@megapathdsl.net> wrote: >>> >>>li...@rtty.us said: >>>> A number of them are sigma delta PLL's and have some really nasty >>>jitter and >>>> spur issues. Anything that shows up listed as "user programmable" - >>>watch >>>> out. >>> >>>But "user programmable" won't find all the nasty ones. >>> >>>I haven't been looking recently. There used to be some that were >field >>> >>>programable. The idea was that the distributor would do it so you >>>didn't >>>have to wait for the factory to grind the crystal to order if you >>>wanted an >>>oddball frequency. They didn't mention the PLL in the data sheet. >You >>>had >>>to read between the lines. >>> >>>I assume the distributor stocked a handful of basic frequencies and >>>there was >>>a PC that told them which one to use and did the programming if you >>>told it >>>what frequency you wanted. >>> >>>It looks like a fun math problem. How many frequencies do you need >to >>>stock >>>in order to cover a given frequency range with a given PLL chip? The >>>result >>>doesn't have to be a direct hit. You can include some fudge as part >of >>>the >>>overall accuracy spec. (If you claim 100 PPM, but cut the crystal >>>within 50 >>>PPM, then you have 50 PPM left for the PLL.) >>> >>> >>> >>>-- >>>These are my opinions. I hate spam. >>> >>> >>> >>>_______________________________________________ >>>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. >> >> -- >> Sent from my Motorola Droid Razr 4G LTE wireless tracker while I do >other >> things. >> _______________________________________________ >> 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. -- Sent from my Motorola Droid Razr 4G LTE wireless tracker while I do other things. _______________________________________________ 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.