Understanding My Crystal Oscillator
Understanding My Crystal Oscillator
(OP)
I have an obsolete, proprietary crystal oscillator. It is a 200MHz, 10 pin, SMT component. The number on the unit is 200N1. I cannot find another C.O. like it in size, number of pins or footprint. What I don't understand is 9 of the pins are grounded. Only one pin is used and it obviously puts out the frequency. How does that work? We have 100s of units we repair with this C.O. in it and they are starting to fail due to age and heat.
What we would like to do is find some comparable C.O., mount it on a small PCB, which in turn would be mounted to the footprint of the old C.O.
I am an electro-mechanical engineering technician, not an engineer. Our EE on staff has no clue, either. Any info would be much appreciated!
What we would like to do is find some comparable C.O., mount it on a small PCB, which in turn would be mounted to the footprint of the old C.O.
I am an electro-mechanical engineering technician, not an engineer. Our EE on staff has no clue, either. Any info would be much appreciated!





RE: Understanding My Crystal Oscillator
4 pins typically have power, ground, out, and N/C. Sounds like your 10-pin has (likely) power, out, and 8 grounds.
Dan - Owner
http://www.Hi-TecDesigns.com
RE: Understanding My Crystal Oscillator
RE: Understanding My Crystal Oscillator
RE: Understanding My Crystal Oscillator
RE: Understanding My Crystal Oscillator
RE: Understanding My Crystal Oscillator
The other possibility is that X1 is a filter. But I'm not aware of filter elements like this applied as a 'shunt-type' arrangement. Filters are usually a in/out type.
RE: Understanding My Crystal Oscillator
RE: Understanding My Crystal Oscillator
As has been stated here and on the other forums... this simply cannot be an oscillator if your schematic is correct. It makes no sense to tie a crystal directly to ground, which leads us to think it's is an oscillator... which means your schematic is wrong.
Something needs to get fixed before we can offer any further useful info.
Dan - Owner
http://www.Hi-TecDesigns.com
RE: Understanding My Crystal Oscillator
RE: Understanding My Crystal Oscillator
http://hem.passagen.se/communication/txo.html
Z
RE: Understanding My Crystal Oscillator
RE: Understanding My Crystal Oscillator
The snippet of schematic does not have the portion needed assess how a standard crystal oscillator might fit into your circuit. The section around IC5 is needed to do that, or, at least, some information about IC5 and where R60 ends up (kind of looks like it's grounded). In any case, R59 is the only possible way an oscillator signal can get to the rest of the board.
Nonetheless, the circuit doesn't make much sense, particularly regarding Q13, since its collector and emitter are shorted by C59? None of the other transistors, Q14, or Q18, are wired for power output through R59. R59 is essentially connected only to the base of Q18 through a capacitor C72, and so R59 appears to be an input, not an output of this circuit. The purpose of L39, which is tied to Vcc and appears to supply power to the transistors and crystal doesn't make much sense, either.
TTFN

FAQ731-376: Eng-Tips.com Forum Policies
Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers
RE: Understanding My Crystal Oscillator
My second guess is that Q13 acts as a capacitance diode for fine-tuning the oscillator.
RE: Understanding My Crystal Oscillator
Dan - Owner
http://www.Hi-TecDesigns.com
RE: Understanding My Crystal Oscillator
IC5 is a mixer p/n ADE 2ASK (another component I'm not familiar with)
More and more, I'm doubting what the manufacturer says about this being an oscillator.
MacGyverS2000 - There are 6 revisions of these units. The oldest dates back 15+ years. The newest I've seen is 2004. They all use the same CO circuitry, though. Yes, I'm sure it's as old as I claim it is...
RE: Understanding My Crystal Oscillator
TTFN

FAQ731-376: Eng-Tips.com Forum Policies
Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers
RE: Understanding My Crystal Oscillator
RE: Understanding My Crystal Oscillator