C20 is a temperature compensation capacitor for the XDCR. Match C20 to the selected XDCR. If XDCR is Murata MA58MF14-7N, 2000-pF capacitance is installed, and 1500-pF capacitance is provided as an alternative. If XDCR is Murata MA58AF14-0N. 1500-pF capacitance is installed. Alternative specifications include: 1500 pF, 0805, 250 V, 20%, NPO