An electrostatic discharge power rail clamp circuit and an integrated circuit including the same. The power rail clamp circuit includes a first power rail, a second power rail and a first node. The circuit further includes an n-channel field effect transistor having a source and drain located in an isolated p-well in a semiconductor substrate. The drain is connected to the first power rail. The source and isolated p-well are connected to the first node. The circuit also includes a capacitor connected between the first node and the second power rail. The circuit further includes a resistor connected between the first power rail and the first node. The circuit also includes an inverter for controlling the gate of the field effect transistor, wherein the inverter has an input connected to the first node. The circuit further a silicon controlled rectifier connected between the first node and the second power rail.