of the scribe line 4 at the chip edge can be used to ground isolated subcircuits so that space is saved on the surface of the chip fig2 shows the equivalent circuit of the arrangement of fig1 the outputs of the hall generator hg which is connected to the supply voltage v dd are applied to differential amplifier dv whose output is coupled to the gate of a field effect transistor ft the drain source path of transistor ft is connected to the bonding pad pd 2 and via resistor r 3 to ground v ss the junction of the source electrode and the resistor r 3 is connected to one end of the resistor r 2 whose other end is coupled to the control input of the differential amplifier dv which has a path to ground through the resistor r 1 the junction of r 1 r 2 and the control input of amplifier dv is connected to one end of resistor r 2 34 whose other end is coupled to the bottom of hall generator hg which has a path to ground through the resistor r 1 39 resistors r 1 r 2 r 3 r 1 39 and r 2 34 represent substrate resistances to avoid cross coupling the values of the substrate resistances must be chosen to fulfill the condition r 2 gt gt r 1 and r 3 3 and r 2 34 gt gt r.