Package-embedded spiral inductor characterization with application to switching buck converters

The design and characterization process of a package-embedded spiral inductor is investigated in this paper via comprehensive electromagnetic simulations. A realistic, multi-layer flip-chip package is considered and modeled in a commercial, full wave electromagnetic simulator. At constant package area, parasitic resistance of a given inductance is minimized. The applicability of the proposed package-embedded spiral inductor to a DC-DC switching buck converter is demonstrated. The flexibility of the package is exploited to obtain a relatively high inductance, enabling a reduced switching frequency. Lower switching frequency minimizes the dynamic loss, thereby increasing the power efficiency. An interleaved multi-phase buck regulator with an array of package-embedded spiral inductors is developed. The extracted layout of the overall circuit is evaluated for performance and primary characteristics. The converter produces an output voltage of 0.9 V from 1.2 V input voltage while supplying a load current of 1 A. Power efficiency of approximately 89% is achieved with 3% output ripple voltage.