Transformer comprising: a substrate having a plurality of layers stacked on top of each other, said layers including a top layer, a bottom layer, and multiple intervening layers (22, 24, 26, 28) disposed between the top layer and the bottom layer, all of the layers providing a multi-moat electrical isolation between an input side and an output side of the substrate, the substrate having an input ground system and an output ground system which is electrically isolated from the input ground system, the input ground system and the output ground system providing continuous return paths for an input signal and an output signal, respectively; the input side having a positive pad and a negative pad in the top layer and a positive connection terminal and a negative connection terminal in the bottom layer, the positive pad and the negative pad being electrically connected to the positive connection terminal and the negative connection terminal, respectively by vertical interconnect access components; the output side having a positive pad and a negative pad in the top layer and a positive connection terminal and a negative connection terminal in the bottom layer, the positive pad and the negative pad of the output side being electrically connected to the positive connection terminal and the negative connection terminal of the output side, respectively by vertical interconnect access components; the connection terminals of the input side being connectable to one section of a medical electrical device and the connection terminals of the output side being connectable to another section of the medical electrical device; a magnetic core mounted on the top layer of the substrate; a primary winding having a first primary end and a second primary end connected to the positive pad and the negative pad of the input side, the primary winding having a middle portion that wraps around the core, an anterior portion between the first primary end and the middle portion, and a posterior portion between the second primary end and the middle portion; a secondary winding having a first secondary end and a second secondary end connected to the positive pad and the negative pad of the output side, the secondary winding having a middle portion that wraps around the core, an anterior portion between the first secondary end and the middle portion, and a posterior portion between the second secondary end and the middle portion; the core transferring data from the primary winding to the secondary winding using magnetic field coupling; wherein the middle portion of the primary winding and the middle portion of the secondary winding are twisted together; and wherein the substrate, core, primary winding, and secondary winding provide an isolation barrier between the sections of the medical electrical device. a substrate having a plurality of layers stacked on top of each other, said layers including a top layer, a bottom layer, and multiple intervening layers (22, 24, 26, 28) disposed between the top layer and the bottom layer, all of the layers providing a multi-moat electrical isolation between an input side and an output side of the substrate, the substrate having an input ground system and an output ground system which is electrically isolated from the input ground system, the input ground system and the output ground system providing continuous return paths for an input signal and an output signal, respectively; the input side having a positive pad and a negative pad in the top layer and a positive connection terminal and a negative connection terminal in the bottom layer, the positive pad and the negative pad being electrically connected to the positive connection terminal and the negative connection terminal, respectively by vertical interconnect access components; the output side having a positive pad and a negative pad in the top layer and a positive connection terminal and a negative connection terminal in the bottom layer, the positive pad and the negative pad of the output side being electrically connected to the positive connection terminal and the negative connection terminal of the output side, respectively by vertical interconnect access components; the connection terminals of the input side being connectable to one section of a medical electrical device and the connection terminals of the output side being connectable to another section of the medical electrical device; a magnetic core mounted on the top layer of the substrate; a primary winding having a first primary end and a second primary end connected to the positive pad and the negative pad of the input side, the primary winding having a middle portion that wraps around the core, an anterior portion between the first primary end and the middle portion, and a posterior portion between the second primary end and the middle portion; a secondary winding having a first secondary end and a second secondary end connected to the positive pad and the negative pad of the output side, the secondary winding having a middle portion that wraps around the core, an anterior portion between the first secondary end and the middle portion, and a posterior portion between the second secondary end and the middle portion; the core transferring data from the primary winding to the secondary winding using magnetic field coupling; wherein the middle portion of the primary winding and the middle portion of the secondary winding are twisted together; and wherein the substrate, core, primary winding, and secondary winding provide an isolation barrier between the sections of the medical electrical device.