When providing differential protection on PoE circuits, a good TVS diode protection scheme must clamp the transient voltage while presenting minimal loading capacitance on the interface. The TVS should offer a low clamping voltage performance and, as a general rule, should provide no more than a pF of line-to-line capacitance. As an additional, unique requirement for PoE circuits, the TVS configuration must account for the presence of the +/-48V DC between line pairs. The high DC voltage on separate pairs will prohibit using any integrated diode array or bridge TVS device to establish an electrical path between line pairs. The differential pairs must be electrically isolated.