The LAN8720A/LAN8720Ai is a low-power 10BASE-T/100BASE-TX physical layer (PHY) transceiver with variable I/O voltage that is compliant with the IEEE 802.3-2005 standards. The LAN8720A/LAN8720Ai supports communication with an Ethernet MAC via a standard RMII interface. It contains a full-duplex 10-BASE-T/100BASE-TX transceiver and supports 10Mbps (10BASE-T) and 100Mbps (100BASE-TX) operation. The LAN8720A/LAN8720Ai 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 cross-over LAN cable

我想很多人都考虑过，当同一块板卡上的两块网口PHY芯片对连的时候，能不能省略两个网络变压器而直接对连呢，答案当然是肯定的。不过我实际操作过后，发现里面还是有很多陷阱，现在给大家一一道来。

88E1510-1518-1512-1514_DATASHEET 页数有一百多页。 M ARVE L LO