3 Key PHY Differences

When migrating from a Standard Ethernet design to a Single Pair Ethernet design, there are several PHY-level differences to consider. Primarily, factors such as size and power consumption should be reviewed. In addition, Standard and SPE PHYs often have differing operating temperature ranges. The following table defines these parameters and how they vary between a Standard and Single Pair Ethernet PHY.

In addition to IC size, it is important to consider the board space required for the implementation of a PHY. For this comparison, the PCB layouts of the DP83826A EVM and DP83TC813-Q1 EVM are compared in the following figures, respectively. Although this is an example of the board space used for a sample application, it shows the general trend that SPE requires less board space than Standard Ethernet.

Board space: Approximately 40mm × approximately 25mm

PHY Body size: 5mm × 5mm

Transformer (T2): 12.7mm × 9.09mm

Board space: Approximately 30mm × approximately 15mm

PHY Body size: 5mm × 4mm

CMC (L1): 4.5mm × 3.2mm

Finally, the form factor differences between Standard Ethernet and SPE must be examined. The different cables, connectors, and other external components contribute to the overall size and weight of the system implementation. These considerations are outlined in Table 3-2. One key advantage of SPE that is demonstrated in this table is the smaller cabling size and weight generally required.