Patent ID: 6914280

Claim:
A switching circuit device comprising: a substrate comprising an insulating region; a first field effect transistor, a second field effect transistor, a third field effect transistor and a fourth field transistor, each of the first, second, third and forth transistors comprising a source electrode, a gate electrode and a drain electrode; a common input terminal connected to the source electrodes or the drain electrodes of the first and second transistors; a first output terminal connected to the source electrode or the drain electrode of the first transistor, which is not connected to the common input terminal, and connected to the source electrode or the drain electrode of the third transistor; a second output terminal connected to the source electrode or the drain electrode of the second transistor, which is not connected to the common input terminal, and connected to the source electrode or the drain electrode of the fourth transistor; a first control terminal connected to the gate electrodes of the first and fourth transistors; a second control terminal connected to the gate electrodes of the second and third transistors; a high-frequency ground terminal connected to the source electrodes or the drain electrodes of the third and fourth transistors, which are not connected to the corresponding output terminals; and a protecting element comprising a first high concentration impurity region, a second high concentration impurity region and at least part of the insulating region of the substrate, said part of the insulating region being located between the first and second high concentration impurity regions, wherein the protecting element is connected between the first output terminal and the gate electrode of the third transistor or between the second output terminal and the gate electrode of the fourth transistor and is configured to discharge at least partially electrostatic energy of external origin through the protecting element so that the electrostatic energy is reduced enough not to provide an electrostatic breakdown voltage between the gate electrode and the corresponding source or drain electrode of the transistor that is connected to the protecting element.