Figure 2-7 shows a representative model of a real-world capacitor component. A capacitor has an accompanying parasitic resistance and inductance, and at very high frequencies the inductance takes over and the capacitor no longer behaves like a capacitor. If the impedance of the capacitor is plotted across a frequency range, the result looks similar to Figure 2-3 but flipped horizontally with the lowest impedance occurring at the resonant frequency.

Capacitors are used in the PoC network for decoupling the input of DC regulators on the serializer side of the link. The input capacitance of the DC regulator is based on both the FPD-Link serializer and DC regulator recommendations found in the device data sheets. The chosen capacitors must have appropriate voltage and temperature ratings for the system. Similarly to how the inductors are cascaded in series to create a wide-bandwidth inductor, capacitors can be cascaded in parallel to create a wide-bandwidth capacitor, or a capacitor that can pass a larger frequency range and better decouple the DC regulators. Often times when choosing a decoupling capacitor, the capacitor can be treated as an ideal capacitor because noise from the DC regulators is at a much lower frequency than the signal frequency trying to be blocked. Equation 2 shows the impedance of a capacitor as a function of frequency, where Z is the impedance in Ohms, f is the frequency in Hertz, and C is the capacitance in Farads.