Integrated voltage regulator (IVR) based power delivery is becoming a necessity in high-performance computing systems. Embedded inductors are key components in such power delivery architectures. In this paper, novel package-embedded inductors using the dual-core spiral topology are designed and demonstrated for 48V-to-1V and 12V-to-1V power conversion applications. This topology consists of a spiral-shaped conductor winding layer sandwiched between dielectric and magnetic core layers. The conductor and dielectric layers separate the cores and act as an air gap for the magnetic flux of the spiral inductor. The air gap causes an increase in the saturation current performance of the inductor. In addition to the single spiral winding, two advanced spiral inductor configurations, namely two spiral windings in series and parallel, are explored. To enable design, monomial analytical expressions for inductance calculations are provided. To evaluate the performance of these designs, three inductors are fabricated with two different magnetic core materials and air gaps. For the large-signal characterization of the fabricated inductors, a current probe-based small-signal resistance scaling methodology is presented. Overall, packageembedded dual-core spiral inductors with a performance of 115 nH inductance with 5 A saturation current and 300 nH inductance with 3.5 A saturation current, occupying a 9 mm 2 area and having 75% to 80% efficiency, are demonstrated.