To achieve optimum performance out of these magnetics certain PCB design guidelines must be followed. Of course, layouts will vary among designers but typical recommendations are as follows: Keep signal traces from IC to magnetics module as short as possible. If traces exceed 3-4 inches, pay close attention to line impedance imbalance and the effects from other signals with high frequency noise, including those carried on power and ground planes. Avoid PCB traces with 90-degree bends to minimize impedance discontinuity. Ensure that there is no contiguous ground plane underneath the module to prevent any digital noise from coupling with signal lines. Using Bob-Smith termination scheme (75 Ω resistors and high voltage capacitor to chassis ground) to terminate cable side CTs is advisable for best EMI performance. Lastly, follow suggested land pattern as shown here.