The LAN8820/LAN8820i is a low-power 10BASE-T/100BASE-TX/1000BASE-T Gigabit Ethernet physical layer （PHY） transceiver that is fully compliant with the IEEE 802.3 and 802.3ab standards. The LAN8820/LAN8820i can be configured to communicate with an Ethernet MAC via the standard RGMII interface. It contains a full-duplex transceiver for 1000 Mbps operation on four pairs of category 5 or better balanced twisted pair cable. Per IEEE 802.3-2005 standards， all digital interface pins are tolerant to 3.6V. The LAN8820/LAN8820i is configurable via hardware and software， supporting both IEEE 802.3-2005 compliant and vendor-specific register functions via SMI. The LAN8820/LAN8820i implements Auto-Negotiation to automatically determine the best possible speed and duplex mode of operation. HP Auto-MDIX support allows the use of direct connect or crossover cables. An internal block diagram of the LAN8820/LAN8820i is shown in Figure 1-1. A typical system-level diagram is shown in Figure 1-2.