Texas Instruments Automotive Ethernet PHY portfolio consists of 100Base-T1 (DP83TC811) and 1000Base-T1 (DP83TG720) devices. Automotive system qualification cycles are time consuming and any significant change in system can lead to increase in development costs. To reduce the complexity of automotive Ethernet system design, TI PHYs were design such that they can be implemented on a single system. This avoids a complete redesign of the system when going from one speed to the other based on the application requirement. To help achieve this both the devices have the same package footprint of 36 pin QFN, 6mm x 6mm.

Apart from the cable side communication speed,MAC interface selection can also affect PCB design. DP83TC811 supports MII, RMII, RGMII, and SGMII MAC interfaces. DP83TG720 supports RGMII and SGMII MAC interfaces. MII and RMII standards were defined only for 10 and 100Mbps only, so DP83TG720 does not support these options. This application report assumes that DP83TC811 will also be operated in RGMII or SGMII mode.