Q: How to calculate external capacitors?

A: We calculate the external capacitors using the formula C1 = C2 = 2 × (CL - Cs), where CL is the required load capacitance and Cs represents parasitic capacitance. The parasitic capacitance is typically 3–5 pF. When selecting external capacitors for a crystal oscillator circuit, we recommend considering the required load capacitance specified for the crystal together with the oscillator circuit requirements.

At SJK, we provide crystal units for different electronic designs, including MHz crystals and 32.768 kHz crystals, as well as SMD crystal resonators in multiple package sizes. Our product portfolio supports frequency-control requirements with a focus on high precision, miniaturization, and low power consumption. By matching the crystal's load capacitance with the circuit design and calculating the external capacitors accordingly, engineers can select a suitable configuration for their application.