Magnetically coupled linear isolator

A linear isolation device has been fabricated using giant magnetoresistance (GMR) thin film structures to sense current in a planar coil across a Si/sub 3/N/sub 4/ insulation barrier. NiFe shields are electroplated to improve signal and shield stray field noise. The devices were connected to an external current replicating circuit realized from discrete components. Measured output characteristics include nonlinearity of less than 1%, and withstanding voltages over 2.5 kV.