Package to printed circuit board transition

Package to printed circuit board (PCB) transitions are described. In one aspect, a multi-layer PCB includes an external layer having a transition region configured to receive an electrical component and a clear routing region outside of the transition region. The PCB includes first via(s) that extend from the transition region to an inner trace routing layer. The trace routing layer is disposed between the external layer and the second inner trace routing layer. The first inner trace routing layer includes a transition area disposed under the transition region of the external layer, a clear routing area outside of the transition region, and a transmission line that connects a given first via to a second via for a second electrical component. The transmission line includes conductive trace(s) that each have a first width in the transition area and a second width, greater than the first width, in the clear routing area.