A transient blocking unit (TBU) having improved damage resistance is provided. A TBU includes two or more depletion mode transistors arranged to provide a low series impedance in normal operation and a high series impedance when the input current exceeds a predetermined threshold. At least one of the TBU transistors is a protecting device having a shunt circuit element connected in parallel with its channel. When the TBU is in its high impedance state, the shunt circuit element provides a current path, thereby decreasing terminal voltages on at least one of the TBU transistors. The shunt element can be a discrete or integrated resistor, a current source including a transistor, or an appropriately engineered device parasitic.