Disclosed herein are various embodiments of coil transducers configured to provide high voltage isolation and high voltage breakdown performance characteristics in small packages. A coil transducer is provided through and across which data or power signals may be transmitted and received by primary and secondary coils disposed on opposing sides thereof without high voltage breakdowns occurring therebetween. A central core layer separates the transmitting and receiving coils, and has no vias disposed therethrough. At least portions of the coil transducer are formed of an electrically insulating, non-metallic, non-semiconductor, low dielectric loss material.