SLLSEJ7 February 2015 DP83848-HT
The device Vdd supply pins should be bypassed with low impedance 0.1-μF surface mount capacitors. To reduce EMI, the capacitors should be places as close as possible to the component Vdd supply pins, preferably between the supply pins and the vias connecting to the power plane. In some systems it may be desirable to add 0-Ω resistors in series with supply pins, as the resistor pads provide flexibility if adding EMI beads becomes necessary to meet system level certification testing requirements. (See Figure 47.)
TI recommends the PCB have at least one solid ground plane and one solid Vdd plane to provide a low impedance power source to the component. This also provides a low impedance return path for nondifferential digital MII and clock signals. A 10-μF capacitor should also be placed near the PHY component for local bulk bypassing between the Vdd and ground planes.