Formulas for this circuit?

[me]

Does anyone here have any formulas for determining the appropriate values
for the Capacitors, resistors, inductor in this circuit for a given
frequency.

http://www.freewebs.com/misc-circuit/LC-Cmos.png

 

[Leon]

Does anyone here have any formulas for determining the appropriate values
for the Capacitors, resistors, inductor in this circuit for a given
frequency.

http://www.freewebs.com/misc-circuit/LC-Cmos.png

It's a Pierce oscillator, so I think the frequency will be dominated by
the parallel LC circuit. C2 and C3 are effectively in series, so won't
have much effect. You could check by simulating it with SPICE.

Leon

 

[John Popelish]

Does anyone here have any formulas for determining the appropriate values
for the Capacitors, resistors, inductor in this circuit for a given
frequency.

http://www.freewebs.com/misc-circuit/LC-Cmos.png

The LC resonant frequency is approximately 1/(2*pi*sqrt(LC)), except
that C is C1 in parallel (added to) the series combination of C2 and
C3 which is 1/((1/C2)+(1/C3)). It is approximate, because it neglects
the capacitance of the input of the NAND gate and stray capacitance.

The resistor is often found by experiment. The higher the resistance,
the higher the Q of the resonance (purer frequency) but the smaller
the signal at the input of the gate, so the more rounded the output
wave, or even lack of oscillation. The selection of C2 and C3 are
also related to the loop gain of the oscillator. They usually work
best if equal, but one, effectively includes the input capacitance of
the gate, so the capacitor shown is smaller than the other.

 

[Mochuelo]

Does anyone here have any formulas for determining the appropriate values
for the Capacitors, resistors, inductor in this circuit for a given
frequency.

http://www.freewebs.com/misc-circuit/LC-Cmos.png

Unless you need really high frequencies, use 4093 (including Schmitt
triggers at all inputs) instead of 4011. Independently, you don't need
two-input gates for this. You can use either 40106 (6 inverters with
Schmitt trigger) or 4049UB.

The exact oscillation frequency depends (among other things) on the
input threshold voltage of the gate. I would run a simulation.

Best,

 

[John Fields]

Unless you need really high frequencies, use 4093 (including Schmitt
triggers at all inputs) instead of 4011. Independently, you don't need
two-input gates for this. You can use either 40106 (6 inverters with
Schmitt trigger) or 4049UB.

The exact oscillation frequency depends (among other things) on the
input threshold voltage of the gate. I would run a simulation.

 

[Fred Bloggs]

Not only- but clearly wrong advice. It was what the clueless OP deserved
nonetheless. Also, IIRC the entire idea stunk as the LC resonance
coincided with the abrupt cut-off frequency of the buffered CMOS.