Crystal Load Capacitance Calculator

This tool calculates the cap values C1 and C2 shown in the picture below from the load capacitance (specified in the data sheet) and the stray capacitance

Calculator

Enter

  • Load Capacitance from the data sheet and
  • Stray capacitance (typically 5 pF but a value between 2 pF and 8 pF can be specified)

The calculator will provide values for C1 and C2


	

			

		

						

				

				

                

			

			
						

		

		











Example Calculations





Use the recommended load capacitance value from the data sheet. In the following example data sheet it is 8 pF. A stray capacitance value of 5 pF gives C1 = C2 = 6 pF










Formula for Load Capacitance Calculator





C1 = C2 = 2*(Cload – Cstray)





Note





It’s important to accurately calculate or estimate Cstray for precise tuning of the crystal frequency. If the actual load capacitance does not match the crystal’s specified load capacitance, the oscillator may operate at an off-nominal frequency, leading to potential communication or timing errors in your application.





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