A stacked integrated circuit includes a first tier IC and a second tier IC. Active faces of the first tier IC and the second tier IC face each other. An interconnect structure, such as microbumps, couples the first tier IC to the second tier IC. An active portion of a voltage regulator is integrated in the first semiconductor IC and coupled to passive components (for example a capacitor or an inductor) embedded in a packaging substrate on which the stacked IC is mounted. The passive components may be multiple through vias in the packaging substrate providing inductance to the active portion of the voltage regulator. The inductance provided to the active portion of the voltage regulator is increased by coupling the through via in the packaging substrate to through vias in a printed circuit board that the packaging substrate is mounted on.