A programmable transformer incorporating windings embedded in a thin film substrate. The windings are flat wire traces embedded into the substrate, primary on one side and secondary on the other. The secondary windings may be planar or different coils spatially arrayed throughout a thickness of the substrate. The secondary winding may include multiple tap points, effectively providing multiple secondary coils referenced to the single primary coil. Each tap point is bridged to a field effect or CMOS transistor path by which a digital controls permit dynamic adjustment of the turns ratio. The final secondary output depends on the activated transistor paths. Multiple secondary outputs from a single secondary coil and a digitally programmable turns ratio are available aspects.