What is stray capacitance

bigbat

What is stray capacitance [Copy link]

Recently I saw ST's crystal oscillator design guide AN2867

“Load capacitance is the capacitance of the terminals of the circuit connected to the crystal oscillator. This value is determined by the external capacitors CL1 and CL2 and the stray capacitance of the printed circuit board and connections (Cs) . The CL value is specified by the crystal manufacturer. In order for the frequency to be accurate, the oscillator circuit must present the same load capacitance to the crystal as it did when the crystal was adjusted. Frequency stability primarily requires that the load capacitance be constant. External capacitors CL1 and CL2 are used to adjust the desired CL value to the value specified by the crystal manufacturer. The following equation gives an expression for CL”

What is stray capacitance? How to determine it?

maychang

Stray capacitance refers to the capacitance between wires, the capacitance between component leads, etc. The first post also says "connection", so the stray capacitance refers to the capacitance between the wires connecting the two ends of the crystal.