CD4060 Xtl Osc. Circuit
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From: Steve Upton on 12 Mar 2010 19:20 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? Or can anyone please provide a similar circuit that works? http://www.redclifferadioclub.org.au/QRM/2006%2010%20-%20October%20QRM.pdf Steve Upton
From: John Larkin on 12 Mar 2010 19:28 On Sat, 13 Mar 2010 00:20:46 GMT, steveupton(a)gerber.com (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? Or can anyone please provide a similar circuit that >works? > >http://www.redclifferadioclub.org.au/QRM/2006%2010%20-%20October%20QRM.pdf > >Steve Upton 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. John
From: Joerg on 12 Mar 2010 19:45 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) -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Chris on 12 Mar 2010 19:45 On Mar 12, 4:20 pm, steveup...(a)gerber.com (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? Or can anyone please provide a similar circuit that > works? > > http://www.redclifferadioclub.org.au/QRM/2006%2010%20-%20October%20QR... > > Steve Upton Steve, this does not strike me as the best circuit for the crystal. I just built a crystal oscillator with a CD4060, and it worked great. What frequency are you using, and what is the capacitance of the crystal? I will make it work on my spice model to test it as well. Regards, Chirs Maness KQ6UP
From: Chris on 12 Mar 2010 19:50
> 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. > I agree, if you want to try to get it going use 2Meg for the 100k resistor and the 2k2 is fine for the power limiting resistor. Try 20pf for both the 100pF and for the 39pF caps. Also put a 20pF trimmer across the xtal to fine tune against a known good frequency. Good Luck, Chris Maness KQ6UP |