Human body ESD voltages are nature-determined and can be 15 kV or more which will damage the IC. The key to selecting over voltage protection is to consider what the equipment needs to be protected against. Therefore, it is common practice to protect all “people interactive” data ports to limit product damage and increase the robustness of the equipment. The external ESD protector then becomes the first level of protection with the IC providing residual second level protection in the design.