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faisal
Joined: 18 Feb 2005
Posts: 8
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 28 Feb 2005 8:09 Calculation of Load Capacitance of A Quartz Crystal |
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Hi,
I have a Quartz crystal (GSCX-39) of Golledge Electronics Ltd.
It has the frequency range of 3.579~70 MHz.
I want to use it in a fixed oscillator of 68.75 MHz.
What load capacitance should be used for this purpose.
Please post a complete circuit diagram if possibe alongwith all
the component values.
With Regards.
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Borber
Joined: 01 Jan 1970
Posts: 1561
Helped: 117
Location: Slovenia
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28 Feb 2005 9:19 Re: Calculation of Load Capacitance of A Quartz Crystal |
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What do you mean by 3.579~70 MHz. Is your crystal made of elastic rubber?
Crystals are made for single, discrete frequency which can be pulled some few 10 ppm.
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faisal
Joined: 18 Feb 2005
Posts: 8
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28 Feb 2005 10:20 Re: Calculation of Load Capacitance of A Quartz Crystal |
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Perhaps yes the crystal is made up super elastic.
If you don't believe it find the data sheet and look for your self the
unbelievable super rubber crystal.
Best of Luck.
http://www.golledge.com/docs/products/xtl_sm/gscx39.htm
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Borber
Joined: 01 Jan 1970
Posts: 1561
Helped: 117
Location: Slovenia
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28 Feb 2005 11:02 Re: Calculation of Load Capacitance of A Quartz Crystal |
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| This type of crystal can be produced within the frequency range of 3.579~70 MHz, but only for specified frequency in this range.
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faisal
Joined: 18 Feb 2005
Posts: 8
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28 Feb 2005 11:20 Re: Calculation of Load Capacitance of A Quartz Crystal |
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| You mean that I have to place the order of 68.75MHz.
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28 Feb 2005 11:20 Ads |
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Borber
Joined: 01 Jan 1970
Posts: 1561
Helped: 117
Location: Slovenia
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28 Feb 2005 11:24 Re: Calculation of Load Capacitance of A Quartz Crystal |
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| Yes, all crystals are single frequency devices there exists no "elastic" type.
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faisal
Joined: 18 Feb 2005
Posts: 8
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28 Feb 2005 11:31 Re: Calculation of Load Capacitance of A Quartz Crystal |
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| You mean that I have to place the order of 68.75MHz.
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brmadhukar
Joined: 21 Jun 2002
Posts: 844
Helped: 29
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28 Feb 2005 12:26 Re: Calculation of Load Capacitance of A Quartz Crystal |
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Hi,
You chose your load capacitances while designing the oscillator inside the IC and once it is done you chose the crystal and the corresponding capacitors. If you can give that load capacitance we can match it.
B R
Madhukar
You may search for this in some of the crystal manufacturers web sites and find and AN
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biff44
Joined: 24 Dec 2004
Posts: 1834
Helped: 244
Location: New England, USA
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28 Feb 2005 12:38 Re: Calculation of Load Capacitance of A Quartz Crystal |
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| The dynamic range of the engineering skill level on this board has to be around 90 dB!
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