Crystal Oscillator Circuit DesignAPPLICATION NOTE
Crystal Oscillator Circuit Design
In this application note we shall discuss our recommended crystal oscillator circuit, explain each component in the circuit and provide some guidelines on selecting values for these components. Finally, we shall give a few precautions to take in order to avoid in-stability and start-up problems.
R L C
Cp
Figure 1. Crystal equivalent Circuit.
Anti-Resonance fa Parallel Resonance
Impedence
Series Resonance
fs
f
Figure 2. Reactance Vs Frequency plot of a crystal. Figure 1. shows the crystal equivalent circuit. R is the effective series resistance, L and C are the motional inductance and capacitance of the crystal. CP is the shunt capacitance due to the crystal electrodes. Figure 2. shows the reactancefrequency plot of the crystal. Whe……