CD4060 Xtl Osc. Circuit
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From: JosephKK on 17 Mar 2010 03:11 On Tue, 16 Mar 2010 18:30:56 -0500, "krw(a)att.bizzzzzzzzzzzz" <krw(a)att.bizzzzzzzzzzzz> wrote: >On Tue, 16 Mar 2010 08:10:55 -0700, "JosephKK"<quiettechblue(a)yahoo.com> wrote: > >>On Sat, 13 Mar 2010 13:15:43 -0600, "krw(a)att.bizzzzzzzzzzzz" <krw(a)att.bizzzzzzzzzzzz> wrote: >> >>>On Sat, 13 Mar 2010 13:53:23 -0500, "Martin Riddle" <martin_rid(a)verizon.net> >>>wrote: >>> >>>> >>>> >>>><krw(a)att.bizzzzzzzzzzzz> wrote in message >>>>news:6qmnp598tm30hlmvgvdne65ps3msbb8q3r(a)4ax.com... >>>>> On Sat, 13 Mar 2010 09:05:24 -0800, John Larkin >>>>> <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >>>>> >>>>>>On Sat, 13 Mar 2010 08:42:27 -0800, Fred Abse >>>>>><excretatauris(a)invalid.invalid> wrote: >>>>>> >>>>>>>On Fri, 12 Mar 2010 16:28:07 -0800, John Larkin wrote: >>>>>>> >>>>>>>> I never buy crystals for things like this. They have a high >>>>>>>> probability of >>>>>>>> not working, and you wind up fiddling with capacitors and such. >>>>>>>> It's >>>>>>>> easier to but a packaged, working crystal oscillator, already tuned >>>>>>>> to a >>>>>>>> couple PPM, guaranteed to oscillate, for $1.50 or thereabouts. >>>>>>> >>>>>>>Me, too. Amplifiers oscillate, oscillators don't ;-) >>>>>> >>>>>>We've just started using silicon oscillators, in SOT-23 sized >>>>>>packages, for things where 1% is good enough. We're using one part >>>>>>that's pin strappable for 8-4-2-1 MHz. >>>>> >>>>> A seven pin SOT-23? >>>> >>>>I think its this Linear part >>>><http://cds.linear.com/docs/Datasheet/6900fa.pdf> >>>>There are others tho. >>> >>>Neat (but sloppy - 1/5% to 2% error). That's a trinary input (1/10/100) in a >>>SOT-23-5. John was suggesting 1-2-4-8 binary inputs. I've never seen a >>>SOT-23-7. Up to six pins on a "SOT-23" I can understand, but where does the >>>seventh pin go? >> >>As a quick guess, perhaps a thermal/power pad? > >SOT-23s with a power pad? I think we got the answer, though. It has been interesting reading. I am about to get an attitude about TQFP and smaller / finer pitch. Just not hand handlable any more (at least for some older folk such as me).
From: JosephKK on 17 Mar 2010 06:05 On Fri, 12 Mar 2010 16:45:06 -0800, Joerg <invalid(a)invalid.invalid> wrote: >Steve Upton wrote: >> I have copied the CD4060 part of the CMOS synthesizer in the link >> below to the letter, but it does not work. I am using a 12VDC SLA for >> supply. It tries to start when I tease the caps, but then dies. >> >> I've spent hours tinkering to no avail. Can anyone see what is might >> be going amiss? ... > > >Not knowing which frequency you are using, the 100k is way too low. I >never go below 1M. Also, the burden caps are highish, 100pF is a bit much. > > >> ... Or can anyone please provide a similar circuit that works? >> > >Yup: > >http://www.edn.com/contents/images/6553623.pdf > > >> http://www.redclifferadioclub.org.au/QRM/2006%2010%20-%20October%20QRM.pdf >> > >How on earth could you guys call your club bulletin "QRM"? ... :-) > >(for non-hams: QRM means noise, of the undesired kind, meaning not from >a rock band and stuff) Perhaps they are disguising that they really should be QRN. Much like the EDN article (no improvement in S/N in 30 years, -10 dB or worse).
From: JosephKK on 17 Mar 2010 06:10 On Fri, 12 Mar 2010 20:55:06 -0500, Phil Hobbs <pcdhSpamMeSenseless(a)electrooptical.net> wrote: >On 3/12/2010 7:45 PM, Joerg wrote: >> Steve Upton wrote: >>> I have copied the CD4060 part of the CMOS synthesizer in the link >>> below to the letter, but it does not work. I am using a 12VDC SLA for >>> supply. It tries to start when I tease the caps, but then dies. >>> >>> I've spent hours tinkering to no avail. Can anyone see what is might >>> be going amiss? ... >> >> >> Not knowing which frequency you are using, the 100k is way too low. I >> never go below 1M. Also, the burden caps are highish, 100pF is a bit much. >> >> >>> ... Or can anyone please provide a similar circuit that works? >>> >> >> Yup: >> >> http://www.edn.com/contents/images/6553623.pdf >> >> >>> http://www.redclifferadioclub.org.au/QRM/2006%2010%20-%20October%20QRM.pdf >>> >>> >> >> How on earth could you guys call your club bulletin "QRM"? ... :-) >> >> (for non-hams: QRM means noise, of the undesired kind, meaning not from >> a rock band and stuff) >> >Nah, noise is QR*N*. QRM is interference, usually other random lusers >gassing about their equipment. > >Cheers > >Phil Hobbs Please recheck Phil, i remember QRN as being QRNovice (pejorative).
From: JosephKK on 17 Mar 2010 06:36 On Sun, 14 Mar 2010 14:29:37 -0700, Jim Thompson <To-Email-Use-The-Envelope-Icon(a)My-Web-Site.com> wrote: >On Sun, 14 Mar 2010 13:34:49 -0700, Joerg <invalid(a)invalid.invalid> >wrote: > >>Jim Thompson wrote: >>> On Sun, 14 Mar 2010 13:25:18 -0700, Joerg <invalid(a)invalid.invalid> >>> wrote: >>> >>>> Jim Thompson wrote: >>>>> On Sun, 14 Mar 2010 09:51:52 -0700, Joerg <invalid(a)invalid.invalid> >>>>> wrote: >>>>> >>>>>> Jim Thompson wrote: >>>>>>> On Sun, 14 Mar 2010 09:05:27 -0700, Joerg <invalid(a)invalid.invalid> >>>>>>> wrote: >>>>>>> >>>>>>>> Jim Thompson wrote: >>>>>> [...] >>>>>> >>>>>>>>> My rule of thumb, which seems to work with every inverter-style >>>>>>>>> crystal oscillator I've ever tried: Use capacitors as recommended by >>>>>>>>> the crystal specification... if it says 15pF, that means 30pF on EACH >>>>>>>>> end to ground. Then choose the resistor based on 45ยบ phase shift with >>>>>>>>> the first capacitor (at the crystal frequency). >>>>>>>>> >>>>>>>> I am usually happy with around 1M. All it needs to do is to crank it >>>>>>>> over. Kaaaa-chum-pah ... POOF ... vrooooom. Unless I must start it >>>>>>>> really fast for some reason but that can require special kicker circuitry. >>>>>>> Huh? You and I are talking two different resistors. I'm talking the >>>>>>> series drive resistor; you're talking the DC loop resistor. >>>>>>> >>>>>> Ok, different thing. Mostly you can get away without although that's not >>>>>> always the nice way of doing things. >>>>>> >>>>>> >>>>>>> Which brings to mind... does the CD4060 have the DC loop resistor >>>>>>> built-in? It would appear not. >>>>>>> >>>>>> AFAIR not. >>>>>> >>>>>> >>>>>>> And I should pay closer attention to details :-( The OP has 100K >>>>>>> there... needs to be 10-20Meg. >>>>>>> >>>>>> I usually go for 1M. >>>>> CD series stuff doesn't have a lot of gm. But 1Meg is good for >>>>> something like 74HCU04. >>>>> >>>> For the CD4060 they recommend even higher values, page 3: >>>> >>>> http://www.fairchildsemi.com/ds/CD%2FCD4060BC.pdf >>> >>> Didn't I say 10-20Meg ?:-) >>>> >>>>> DO NOT USE buffered inverters for crystal oscillators! >>>>> >>>> Depends on the frequency but generally yes, don't use those if you can >>>> avoid it. >>> >>> Makes for lousy stability and possible non-starts. >>> >> >>I never had those problems. But I also prefer non-buffered inverters for >>that. >> >>>> >>>>>> 10M may not work outdoors when humidity is high and >>>>>> some condensation occurs. >>>>> Mine are usually on-chip :-) >>>>> >>>> Yup, a poly resistor is nice. But you can't put crystals on the chip :-) >>> >>> Wanna bet ?:-) >>> >> >>With MEMS you could, lots of things are possible. But unlikely as good >>as a real crystal. > >You _can_ mount a membrane type crystal onto a chip, though, right >now, we're mounting the crystal separately... hybrid board style. > > ...Jim Thompson Excuse my ignorance, but that sounds very scary. Physical mode control would have to be very reliable; else there could be unwanted transferred mechanical stresses.
From: JosephKK on 17 Mar 2010 06:47
On Sun, 14 Mar 2010 16:10:43 -0500, Vladimir Vassilevsky <nospam(a)nowhere.com> wrote: > > >Joerg wrote: > >> Vladimir Vassilevsky wrote: >> >>> >>> >>> Joerg wrote: >>> >>>> Yup, a poly resistor is nice. But you can't put crystals on the chip :-) >>> >>> >>> Isn't it what Maxim does in their clock ICs ? >>> >> >> I never use Maxim parts. If you mean the former Dallas series 32kHz >> things those are modules that contain a tuning fork crystal. They may >> look like a chip but in reality it's modules. And my clients would >> probably have my head examined if I placed a timing clock oscillator >> that costs several Dollars :-) > >There are not too many choices when you need an RTC. Besides, some >Dallas/Maxim parts offer the ability to adjust the clock frequency >digitally, so you can phase lock it to external signal. That's not too >bad for few dollars. > >VLV May i suggest that both of you reacquaint yourselves with NTP (network time protocol). It is an intentionally very simple protocol, with intentionally very useful byproducts. |