Passive frequency compensation with coil pairs

A method of making a frequency-compensating current sensor, the method comprising:

• providing a first coil disposed on a first substrate and defining a first footprint on the first substrate, wherein the first coil is configured for inductive coupling with an ambient magnetic field;
• providing a second coil disposed on a second substrate and defining a second footprint on the second substrate, wherein the second coil is disposed within the first footprint, wherein the second footprint is smaller than the first footprint, and wherein the second coil is connected to the first coil;
• and
• providing a magnetic field sensor disposed within the second footprint and including a plurality of magnetic field sensing elements connected to an integrated circuit (IC), wherein the magnetic field sensor is configured to detect the ambient magnetic field and a compensating magnetic field produced by the second coil, and produce an output signal indicative of a current producing the ambient magnetic field;
• wherein the first coil is configured to provide an increasing current as the frequency of the ambient magnetic field increases and provide the increasing current to the second coil to compensate for a frequency-dependent coupling factor between the magnetic field sensor and the ambient magnetic field.