I want to build a phase-lockable VCXO using one of these tiny 100 KHz tuning fork (cylinder-type) crystals:
I've got it to oscillate using the classic unbuffered CMOS inverter circuit with a 5V supply, two 33pF loading caps, 1M feedback resistor and 100k current-limiting resistor. This may still be too much drive - the datasheet says 1uW max.
Is this a suitable circuit for these crystals? Can anyone recommend a better circuit?
TIA
Check the input side of the inverter with a hi-Z 'scope probe. If it's significantly less than rail-to-rail and looks sinusoidal you should be OK.
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
America: Land of the Free, Because of the Brave
ing
it
sheet
that was the easy part..
now how are you going to make it voltage controlled?
Mark
OK. Simply make a voltage-controlled capacitance multiplier ;-)
...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC\'s and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
America: Land of the Free, Because of the Brave
'tis why varicap diodes were invented. But you'll have to use another inverter (preferably a Schmitt) and some discretes to provide 15V or so.
-- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
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