Abstract: Generally provided is a circuit assembly construction for controlling impedance in an electronic package. A large scale, parallel-plate capacitor includes two electrodes separated by a dielectric material. The electrodes serve as reference voltage planes for the electronic package. At least one of the electrodes is patterned such that both electrodes are accessible from a common side of the capacitor. The capacitor is positioned with a first electrode mounted adjacent to an interconnect circuit portion of the electronic package. An electronic device portion of the electronic package is electrically connected, directly or indirectly, to one or more of the electrodes of the capacitor.