A multi-voltage domain device includes a circuit substrate comprising a first region comprising first circuitry, a second region comprising second circuitry, and an isolation region that electrically isolates the first region and the second region in a lateral direction; an insulator layer arranged on the circuit substrate; a first coil arranged in the insulator layer and electrically coupled to the first circuitry; a second coil arranged in the insulator layer, electrically coupled to the second circuitry, and laterally separated from the first coil in the lateral direction by an insulator material of the insulator layer. The first coil and the second coil are U-shaped coils with opposing coil ends being aligned with each other across the isolation region for magnetic coupling.