An integrated circuit includes an UTBOX insulating layer under and plumb with first and second electronic components, and corresponding ground planes and oppositely-doped wells made plumb with them. The wells contact with corresponding ground planes. A pair of oppositely doped bias electrodes, suitable for connecting corresponding bias voltages, contacts respective wells and ground planes. A third electrode contacts the first well. A first trench isolates one bias electrode from the third electrode and extends through the layer and into the first well. A second trench isolates the first bias electrode from one component. This trench has an extent that falls short of reaching an interface between the first ground plane and the first well.