The LAN8720A-CP-TR is a 10/100 Ethernet PHY transceiver from Microchip in QFN-24, with RMII interface to the MAC. The CP-TR suffix specifies commercial temperature (0C to +70C), tape-and-reel. The PHY encodes transmit data using 4B/5B and MLT-3 encoding for 100Base-TX, or Manchester encoding for 10Base-T. The differential transmit pair (TXP/TXN) drives the Ethernet magnetics, and the receive pair (RXP/RXN) recovers data from the line. The RMII interface uses 7 signals at 50MHz clock, reducing pin count versus MII. The 25MHz crystal on XTAL1/XTAL2 provides the reference; REF_CLK outputs 50MHz to the MAC. The MDIO/MDC management interface provides access to 32 internal registers for configuration and status monitoring. Auto-negotiation selects the highest common speed/duplex with the link partner. The HP Auto-MDIX feature automatically detects and corrects for crossover cables (straight-through vs crossover), eliminating the need for specific cable types. The RBIAS pin connects a 12.1k-ohm resistor to GND for transmit bias. The VDDCR output provides 1.2V for the internal core, requiring 2.2uF decoupling. The device consumes 45mW at 100Mbps and supports IEEE 802.3az energy-efficient Ethernet. The nINT pin generates interrupts on link status changes, enabling the MCU to poll less frequently.