Common mode noise voltage will always be present between the transmit and receive grounds. For this reason, some of the current will be flowing through the shield. To further increase the performance, users need simply to increase the impedance of the device. Here, this slide will start with the top left diagram, finishing at the bottom left diagram. Würth has gone from a failure rate of 0.34% to 0% simply by increasing impedance from 32 Ω on the common mode side and 0.7 Ω on the differential side to 363 Ω on the common mode side and 1 Ω on the differential side. This example shows the signal performance at 12MHz using a common mode choke.