An electrostatic discharge (ESD) protection circuit includes an ESD detector connected between a pad and a first power source and configured to generate a detection signal when ESD is detected at the pad, a switch transistor including a gate controlled by the detection signal and a source and a drain connected between the pad and the memory, and a leakage current prevention circuit including a first transistor including a first gate connected to a second power source and a source and a drain connected between the pad and a first node, and a second transistor including a second gate connected to the pad and a source and a drain connected between the first node and the second power source. The first node is connected to or in electrical communication with a bulk node of the switch transistor.