9.3.2 Electrical Fast Transient (EFT) Protection

Inductive loads such as relays, switch contactors, or heavy-duty motors can create high-frequency bursts during transition. The IEC 61000-4-4 test is intended to simulate the transients created by such switching of inductive loads on AC power lines. Figure 20 shows the voltage waveforms in to 50-Ω termination as defined by the IEC standard.

Figure 20. EFT Voltage Waveforms

Internal ESD protection circuits of the THVD14x9 protect the transceivers against EFT ±4 kV.