TLK100 Ethernet PHY Transformerless Operation

The TLK100 is a single-port Ethernet PHY for 10BaseT and 100Base TX signaling. This application report describes a method for using Texas Instruments Ethernet PHY products without a transformer. A transformerless mode has great benefit in the following scenarios: nontypical applications that are sensitive to cost; short-distance, PCB connections (compromises cable reach); and industrial temperature operation. This application report describes how to use the TLK100 Ethernet PHY in a transformerless mode. Also described are the schemes for configuring the TLK100 in this mode and the resulting behavior and performance of the PHY.