Shown here is an EMI scan being conducted without and with discrete ESD protection of a CAN transceiver reference board. An EMI scanner measures the current density and visualizes the current flow on the PCB. It is similar to a heat map scale where blue color represents low current and red color represents high current. In the left picture without ESD protection, a red trail with very high current flowing from the connector into the IC is causing a malfunction. By adding external ESD protection on the right side, the majority of current is clamped to ground at the top instead flowing into the IC. In this scenario, the increased system level robustness prevents damage and application failure.