Abstract: The invention relates to an integrated CMOS circuit for use at high frequencies with active CMOS components (12) and passive components (16, 18, 20). The active CMOS components (12) are formed in a semiconductor substrate (10) which has a specific resistivity in the order of magnitude of k&OHgr;cm. In the semiconductor substrate (10), and under the active CMOS components (12), a buried layer (22) is formed which has a specific resistivity in the order of magnitude of &OHgr;cm. The passive components (16, 18, 20) are formed in or on a layer (14) of insulating material which is arranged on the semiconductor substrate (10). A conducting contact layer (24) is arranged on that surface of the semiconductor substrate (10) which is not facing the layer (14) of insulating material.

Abstract: An electrostatic discharge protection circuit 11 coupled between an input pad 12 and operational circuitry 20 includes a primary clamp circuit 14 coupled to input pad 12, and a current limit circuit 16 coupled to primary clamp circuit 14. Primary clamp circuit 14 clamps an electrostatic discharge voltage to a first voltage value. Operational circuitry 20, susceptible to damage due to an electrostatic discharge, is coupled to current limit circuit 16 and a zener diode 30 is coupled between current limit circuit 16 and a ground potential. Zener diode 30 has a cathode terminal coupled to current limit circuit 16 and an anode terminal coupled to ground potential. Zener diode 30 further clamps a voltage across operational circuitry 20 to a second voltage which is less than 10 V, thereby protecting operational circuitry 20 from damage due to electrostatic discharge.