Done it many times, as an industrially important process: drive it with a
voltage and phase lock on current. Or for a general resistance source
(rather than ideal voltage source), you'll assume drive voltage (internal
clock) and measure the pin voltage to infer current. Under the
restriction Rds(on) sqrt(L/C), but not by too much, so that the signal
is not too small, nor the Q too low.

This will likely restrict what range of L, C can be used, since you get Q
* VCC volts on them and Rds(on) ~ 50 ohms for average HC scale CMOS. And
I(pin) 10mA or whatever, and probably quite a bit below that if it's a
low power application.

Maybe not as bad if it's a low voltage CMOS process where you can get low
resistance cheaply, but then you need another supply (but hey... maybe
make it variable and add AGC?). Or maybe it's reasonable to build a low
impedance analog output pin, so the amplitude is small (optionally
variable), and low impedance.

You could also do what every crystal ever does: add a loading cap, so your
circuit effectively spans a capacitive divider that's part of the resonant
capacitor. Crystals having the unique distinction of extremely large
inductance and extremely small capacitance (the motional equivalent
components), so that the impedance is still rather high (~kohms); a low
impedance resonator would need a respectively large loading cap.

If you need a "discrete"* style oscillator (a few transistors and
resistors rather than an entire loop), it should be fruitful to look at
the V-I transform of a traditional parallel resonant circuit.

*Funny way to put it, since it's going inside a chip...

Tim

--
Seven Transistor Labs
Electrical Engineering Consultation
Website: http://seventransistorlabs.com

"Jim Thompson" wrote
in message ...
Oscillator Proposal...

Suppose I have a series RLC, one end grounded, the other end driven by
a chip, how might I make that into an oscillator?

All wild ideas accepted... this is for a custom chip.

...Jim Thompson
--
| James E.Thompson | mens |
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| Voice480)460-2350 Fax: Available upon request | Brass Rat |
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