Crystal Equivalent Circuit - RF Cafe Forums
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Post subject: Crystal Equivalent Circuit Posted:
Tue Jul 08, 2008 6:42 pm
Joined: Tue Feb
27, 2007 6:16 am
I wish to design and
simulate a crystal oscillator. I have been having great difficulty obtaining
typical crystal equivalent circuit values for whatever frequency.
Can anyone suggest a manufacturer that lists the equivalent
circuit values for each of their crystals?
Other than measuring
the values, is there an easier way of obtaining typical crystal equivalent
Darcy Randall, Perth, Western Australia
Post subject: Posted: Wed Jul 09, 2008 4:12 am
Joined: Fri Feb 17, 2006 12:07 pm
you will find the equivalent circuit and
much useful data on www.euroquartz.co.uk
Post subject: Posted: Wed Jul 09, 2008 11:40 am
Joined: Tue Jul 08, 2008 7:15 pm
Most manufacturers will specify Rm (series
resistance at resonance), Co (holder capacitance) and of course Fo,
so all you really need to complete basic model is either Cm, Lm or Q.
Frerking lists the following typical Qs:
200 KHz Fundamental
2 MHz Fundamental - 54e3
30 MHz 3rd Overtone - 1e5
90 MHz 5th Overtone - 85e3
Many manufacturers will allow
you to specify Cm or Lm, but this is not typically specified on data
sheet since it makes little difference for clock oscillator, where most
crystals are used, and it would add cost to actually measure it in manufacturing.
Hope this helps.
Post subject: Posted: Wed Jul 09, 2008 6:35 pm
Joined: Tue Feb 27, 2007 6:16 am
I have what I need. Cheers
Randall, Perth, Western Australia
subject: Posted: Thu Jul 10, 2008 3:41 pm
Joined: Mon Jun 27, 2005 2:02 pm
Try also Fox Elecctronics: http://www.foxonline.com/
They have detailed specifications for their crystals and good
application notres on their website. I had the sdame problem as you
and they helped me a lot.