4.3.5.1. Channel AC Coupling Capacitors
Each Lane of a PCI Express Link must be AC coupled. The minimum and maximum values for the capacitance is given in Table 4-10. Capacitors must be placed on the transmitter side of an interface that permits adapters to be plugged and unplugged. In a topology where everything is located on a 5 single substrate, the capacitors may be located anywhere along the channel. External capacitors are assumed because the values required are too large to feasibly construct on-chip.