A surge protection device for providing bidirectional detections of one or more surge events. The device has low dynamic resistance during a surge protection mode, and it conducts ultra-low leakage current outside of the surge protection mode. In one implementation, the device includes first and second power transistors, a sensing circuit, and a driver circuit. The first power transistor includes a first source terminal that is coupled to the substrate, and the second power transistor includes a second source terminal that is coupled to the substrate. The sensing circuit is configured to detect a voltage of the first pin relative to the second pin and generate a sense signal when the voltage exceeds a threshold. The driver circuit is configured to generate a driver signal based on the sense signal and output the driver signal to at least one of the first or second gate terminal.