Power delivery network (PDN)
Beginner
All the wiring that carries electricity from outside the chip to every tiny switch inside it.
Novice
Everything that carries the supply from the voltage regulator on the circuit board, through the chip’s package and into the chip, down to every logic cell, plus the capacitors along the way that steady the voltage.
Expert
Treated on chip as a large mesh of resistors (with capacitance, and sometimes inductance, added for time-varying analysis), fed by voltage sources at the bumps and loaded by the current each cell draws. It is judged by voltage drop, wire wear-out (electromigration), how steady the supply stays when demand jumps, and how much routing space it takes from signal wires.
Explained in Power planning (Design Flow).
See also: IR drop, Power strap (stripe), Standard-cell power rail (followpin).