I've used the formula "CL = (C1 * C2) / (C1 + C2) + Cstray" (where C1 = C2) to calculate the capacitors I need for my board. CL is 18pF, I ballparked Cstray at 5pF, meaning I should use 26pF capacitors. When I did so, I got this waveform:
Note that the center line is 0V, so this seems to have a good amount of swing above 0V, but then freaks out and doesn't go below it.
I don't feel like I understand the operation of this very well, and I'm trying to decide if this means I need more capacitance or less. Is this an expected waveform, or have I done something wrong?