The pinout of Texas Instruments High Speed Interface (HSI) devices features differential signal pairs and the remaining signals comprise the supply rails, VCC and ground, and lower speed signals such as control pins. As an example, consider a device X which is a repeater/re-driver, so both its inputs and outputs are high-speed differential signals. These guidelines can be applied to other high-speed devices such as drivers, receivers, multiplexers, and so on.

A minimum of four layers is required to accomplish a low EMI PCB design. Layer stacking should be in the following order (top-to-bottom): high-speed differential signal layer, ground plane, power plane and control signal layer.

Figure 8-7 Layer Stack