An inductor structure implemented within a semiconductor integrated circuit (IC) can include a coil of conductive material that includes a center terminal located at a midpoint of a length of the coil. The coil can be symmetrical with respect to a centerline bisecting the center terminal. The coil can include a first differential terminal and a second differential terminal each located at an end of the coil and opposite the center terminal. The inductor structure can include an isolation ring surrounding the coil. In some cases, the inductor structure can include a return line of conductive material positioned on the center line.