Powering ETH Controllers
DVDDH is the digital IO supply, which must match the other device's RGMII IO voltage. AVDDH is the tranceiver analog supply. They can come from same 3.3V supply if they both need to be 3.3V anyway. Decoupling one supply voltage into the digital and analog supplies with ferrite beads is good enough like in the reference design. There is no mention that these supplies should be separate.