The KS8721CL is a 10BASE-T, 100BASE-TX, and 100BASEFX physical layer transceiver providing MII/RMII interfaces to MACs and switches. Using a unique mixed-signal design that extends signaling distance while reducing power consumption, the KS8721CL represents Micrel’s fourth generation single-port Fast Ethernet PHY. The KS8721CL contains 10BASE-T physical medium attachment (PMA), physical medium dependent (PMD), and physical coding sub-layer (PCS) functions. It also has on-chip 10BASE-T output filtering. This eliminates the need for external filters and allows a single set of line magnetics to be used to meet requirements for both 100BASE-TX and 10BASE-T.