Not only that. Good luck finding a datasheet with *any* analog specifications for its internal oscillator. Here are the pins for an external crystal. The microchip PICs are nice, they give you the goldilocks selection for drive level a little cool, a little hot, maybe just right.
On Tue, Mar 14, 2017 at 8:04 AM, Bob Camp <kb...@n1k.org> wrote: > Hi > > > On Mar 14, 2017, at 4:44 AM, Hal Murray <hmur...@megapathdsl.net> wrote: > > > > > > artgod...@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 > > engineering time. > > Purchased in volume, the difference it the price of a crystal vs a > complete XO > is enormous. You will see at least a 10:1 cost savings on the crystal and > likely > more than that. Simply attaching a crystal to the internal oscillator > inside a > chip is nearly zero engineering cost. If your product is cost sensitive > and > not super tight tolerance … you go with the crystal. > > Bob > > > > > 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. > > > > > > > > _______________________________________________ > > time-nuts mailing list -- time-nuts@febo.com > > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > > and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/ > mailman/listinfo/time-nuts > and follow the instructions there. > _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.