[time-nuts] Bye-Bye Crystals
hmurray at megapathdsl.net
Tue Mar 14 04:44:34 EDT 2017
artgodwin at gmail.com said:
> I'm not after quality - I do have an application in mind but it doesn't need
> to compete with mass production. Just wondering if it's feasible to make
> something crude that will resonate.
Are you doing this for fun or ???
Feasible? Sure. Cheaper? That depends.
The cost difference between a complete oscillator package and a simple
crystal is tiny. The osc is often cheaper if you include board space or
Is your background digital or analog? Do you want a sine wave or a clock?
My background is primarily digital. If the chip you are using has 2 pins
setup to drive a crystal, you can probably get it to run reliably by
following the data sheet and/or app notes. The usual recipe is 2 tiny caps
and a big resistor. (big in resistance, not physically big)
An advantage of using a crystal with the on-chip amplifier that I didn't
mention last time is that you save the osc power if you power down that
corner of the chip.
If you want a sine wave, you are out of my comfort zone. I'd probably look
in ham radio literature.
They make logic chips like a 74HCU04, U for unbuffered. One of their uses is
for making oscillators. I've never done it. Try google.
These are my opinions. I hate spam.
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