MAGNETIC FIELD SENSOR INTEGRATED CIRCUIT WITH INTEGRAL FERROMAGNETIC MATERIAL

A magnetic field sensor includes: a lead frame having a first surface, a second opposing surface, at least one slot extending from the first surface to the second surface in a vertical direction, and a plurality of leads; a semiconductor die having a first surface in which a magnetic field sensing element is disposed and a second opposing surface attached to the first surface of the lead frame, wherein the at least one slot is aligned with the semiconductor die in the vertical direction; a non-conductive mold material enclosing the die and at least a portion of the lead frame, the non-conductive mold material having a first surface adjacent to the first surface of the semiconductor die and a second opposing surface adjacent to the second surface of the lead frame, wherein the non-conductive mold material comprises a protrusion having tapered side walls extending from the second surface of the non-conductive mold material; and a conductive coil secured to the second surface of the non-conductive mold material and positioned concentrically with respect to the protrusion of the non-conductive mold material, wherein the conductive coil is configured to operate as a back bias magnet to provide a magnetic field used to detect movement of a target.