I have been watching/testing the 10MHz TCVCXO that I installed to replace the master clock on the Propeller (see
previous posts). The stability is better than I had hoped, but the installation was NOT as good. I just soldered the TCVCXO onto the
Propeller Protoboard where pads were available, but spacing was not optimal as solder bridges where necessary to make it fit. It was a
jury-rig just to do some initial test.
Now that I had time to think about how it should be mounted, I decided to build a small PCB to hold the the parts; TCVCXO, by-pass cap, two fixed resistors, a variable tuning resistor, and a output cap.
Keeping with my on-going project goal, I wanted it to be as small as my ability allow. The results was a PCB that is 0.453 inches by 0.492 inches. The circuit will stand on three legs/pins which insert into mating sockets. I installed the sockets on the Prop Protoboard using existing holes, which provide 3.3v, ground and the clock input.
If the TCVCXO can not to be used, or if I want to use the original crystal, it can be re-inserted. Only the three pin-sockets were necessary and they can be abandoned.
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DipTrace Layup |
I will have the board made by a commercial PCB vendor, but for a quick test, I resorted to my tried-and-true Toner Transfer Method.
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Circuit at Different Stages of Toner Transfer I made more than one copy, Just in case Murphy was Watching |
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Components Loaded and Ready to Install |
Some things just looks Ugly, when you get TOO close.
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The TCVCXO PCB, Two Fixed Resistors and Pot in Foreground 10MHz TCVCXO Center Two Cap's in at the Far Edge |
Using the board, is just a matter of changing the clock parameters and plugging the TCVCXO in.
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TCVCXO Installed on the Prop Protoboard |
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It Sets Just Below the Edge of the LCD |
I was easy to do, and it works GREAT!
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