A mechanism for continuously referencing signals over multiple layers in laminate packages provides a continuous path for signals from one layer to another while using the ideal voltage reference for all areas of the package and still avoiding discontinuities in the voltage reference. A reference plane adjustment engine analyzes a package design and identifies an ideal top plane for all areas of the package, including areas under particular chip die(s) and areas that are not under a chip die. The reference plane adjustment engine then modifies the package design to reposition ground planes, source voltage planes, signal planes, and vias between layers to maintain a continuous voltage reference regardless of the top layer. The reference plane adjustment engine provides the resulting mixed voltage plane package design to a design analysis engine. A package fabrication system fabricates the package.