Some embodiments relate to an area efficient electrostatic discharge (ESD) clamp comprising an RC trigger circuit, having one or more low-voltage, thin-oxide devices, which is configured to operate with a high-voltage power supply. In some embodiments, the ESD clamp comprises an RC trigger circuit connected between a first circuit node having a first voltage and a second circuit node having a second voltage. The RC trigger circuit comprises a resistive element connected in series with a thin-oxide MOS capacitor. The MOS capacitor has a source and drain connected to an intermediate supply voltage between the first and second voltage, and a body connected to the second voltage. By connecting the source and drain to the intermediate supply voltage, the thin-oxide MOS capacitor is able to reliably operate with a high-voltage power supply.