General Description
The KS8721CL is a 10BASE-T, 100BASE-TX, and 100BASE FX 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.

FEATUREs
• Single chip 100BASE-TX/100BASE-FX/10BASE-T physical layer solution
• 2.5V CMOS design; 2.5/3.3V tolerance on I/O
• 3.3V single power supply with built-in voltage regulator;
   Power consumption <340mW (including output driver current)
• Fully compliant to IEEE 802.3u standard
• Supports MII and Reduced MII (RMII)
• Supports 10BASE-T, 100BASE-TX, and 100BASE-FX with far-end-fault (FEF) detection
• Supports power-down and power-saving modes
• Configurable through MII serial management ports or via external control pins
• Supports auto-negotiation and manual selection for 10/100Mbps speed and full-/half-duplex modes
• On-chip, built-in, analog front-end filtering for both 100BASE-TX and 10BASE-T
• Available in Lead-free and Industrial Temperature packages.
• LED outputs for link, activity, full-/half-duplex, and speed
• Supports back-to-back, FX to TX for media converter applications
• Supports MDI/MDI-X auto-crossover
• Commercial temperature range: 0°C to +70°C
• Industrial temperature range: –40°C to +85°C
• Available in 48-pin LQFP