The KSZ9031RNX is a completely integrated triple-speed (10Base-T/100Base-TX/1000Base-T) Ethernet physicallayer transceiver for transmission and reception of data on standard CAT-5 unshielded twisted pair (UTP) cable. The KSZ9031RNX provides the reduced gigabit media independent interface (RGMII) for direct connection to RGMII MACs in gigabit Ethernet processors and switches for data transfer at 10/100/1000Mbps. The KSZ9031RNX reduces board cost and simplifies board layout by using on-chip termination resistors for the four differential pairs and by integrating an LDO controller to drive a low-cost MOSFET to supply the 1.2V core. The KSZ9031RNX offers diagnostic features to facilitate system bring-up and debugging in production testing and in product deployment. Parametric NAND tree support enables fault detection between KSZ9031 I/Os and the board. The LinkMD® TDR-based cable diagnostic identifies faulty copper cabling. Remote and local loopback functions verify analog and digital data paths.