Figure 9-6 provides a phase noise plot for the 25MHz clock output from the device.
A. This measurement is taken on a DP83867 configured as a Follower. The PHY is linked
to another DP83867 configured as the Leader. Both devices had
PRBS enabled (BISCR, register 0x0016, configured to 0xD000).
B. The phase noise on the CLK_OUT pin before linkup and after link up with no packets being generated are expected to be lower than pictured.