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 packageembedded 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.