A typical operation for the TVS3301 would be protecting an analog output module on a PLC similar to Figure 10-2. In this example, the TVS3301 is protecting a 4-20 mA transmitter that uses the XTR115, a standard transmitter that has a nominal voltage of 24 V and a maximum input voltage of 40 V. Most industrial interfaces such as this require protection against ±1 kV surge test through a 42-Ω coupling resistor and a 0.5-µF capacitor, equaling roughly 24 A of surge current. The system also requires protection from reverse wiring conditions. Without any input protection, this input voltage will rise to hundreds of volts for multiple microseconds, and violate the absolute maximum input voltage and harn the device if a surge event is caused by lightning, coupling, ringing, or any other fault condition. TI's Flat-Clamp technology provides surge protection diodes that can maximize the useable voltage range and clamp at a safe level for the system.