Pierce gate oscillator

[fabiodl]

For a pierce-gate crystal oscillator, are there logic families to avoid?
I am thinking of using a SN74LVC1G04DCKR, any possible pitfalls?
I do not care about the duty cycle, because I purposefully choose a double frequency oscillator and use a flip flop.
(the frequency is pretty unusual, and there are no clocks with such frequency)

[Benta]

For this kind of use, you should choose unbuffered gates.

In this case: 74LVC1GU04.

Buffered vs. unbuffered is a bit like the difference between picking a guitar string with a hammer or with a plectrum. 

What frequency? If it's a 32768 Hz or similar "tuning fork" crystal, it needs a large series resistor, as maximum drive level is only 1 uW.

[fabiodl]

Your example fits perfectly! Does it still hold true when a resistor (R16 in the attached schematic) is used?
The frequency is 21.47727MHz, I was thinking about using a 2k2 and 1M resistor,
but 5**2/2k2 is 11uW!

Should I increase R16?

[Benta]

No problem, your circuit should be OK. The 1 uW drive is only relevant for the low frequency crystals.

[Ian.M]

In another topic, Zero999 suggested the 74LVC1GX04 for Pierce oscillators, as it has one unbuffered inverter for the actual oscillator, and a second buffered inverter to provide a squared up, buffered output to external loads.   I agree. 

[fabiodl]

That's neat!

[Zero999]

In another topic, Zero999 suggested the 74LVC1GX04 for Pierce oscillators, as it has one unbuffered inverter for the actual oscillator, and a second buffered inverter to provide a squared up, buffered output to external loads.   I agree. 

There's also the 74LVC1401, which has a shut down pin, a buffer, as well as the Schmitt trigger.

[Benta]

In another topic, Zero999 suggested the 74LVC1GX04 for Pierce oscillators, as it has one unbuffered inverter for the actual oscillator, and a second buffered inverter to provide a squared up, buffered output to external loads.   I agree. 

I'd forgotten that one. Really nice part.