Patent ID: 7408752

Claim:
An electrostatic discharge protection circuit for an input/output signal terminal in an integrated circuit, coupled to ground, the electrostatic discharge protection circuit comprising: a diode string coupled to the input/output signal terminal; a transistor switch having its gate coupled to the diode string, the transistor switch coupling the input/output signal terminal to ground in parallel to the diode string and triggered by a resistor and a single diode connected in series coupled to ground so that the number of electronic components is reduced, a smaller chip area used, and a compact design and lower cost realized; a capacitive element in series with the transistor switch to reduce the capacitance contributed by the transistor switch, suppress leakage current, improve linearity and improve RF power efficiency; and a reverse diode coupling ground to the input/output signal terminal, where the transistor switch comprises a Darlington pair and the capacitive element comprises a diode.