Air-core transformer package with ferrite electro-magnetic interference (emi) shielding of integrated-circuit (ic) chip

Abstract

An Integrated Circuit (IC) package has a ferrite-dielectric shield between planar transformer coils and a semiconductor chip. The shield blocks Electro-Magnetic Interference (EMI) generated by currents in transformer coils from reaching the semiconductor chip. Multiple layers of planar transformer coils serve as primary or secondary coils and can be connected together in series or parallel using center posts and coil extensions from outer coil windings to lead-frame risers that also have external package connectors such as pins or bonding balls. The center winding of an upper transformer coil connects to the semiconductor chip on a die attach pad through a center post that fits through an opening in the shield that is over the air core center of the transformer coil. Bonding wires connect pads on the semiconductor chip to lead-frame pads on lead-frame risers that end at external package connectors.