Crystal confusion

Doing a DIY Shruthi here. Sourcing a crystal and reading up about the capacitors and the crystal load capacitance.

So the crystal load capacitance is 18pf. Reading a few bits and pieces and looking at the schematic…
So calculations seem to say that if the two caps on either side of the crystal are the same value you use
Load Capacitance = C/2 + Stray Capacitance of circuit.

That being the case shouldn’t the cap values be in the 30pf region to give a total load capacitance between 13-15pf (using the 3/5pf stray capacitance rule of thumb)?

I mean obviously it all works there’s loads of these out there just wanting to understand this better :smiley:

You’re right. This mistake is all over the place on devboard’s schematics, and I contributed to its propagation.

Phew thanks Olivier, thought I’d missed something obvious with the calculator.
I’ll stick with 18pf mistake or not since it works!ta