Voltage Drop Console

A power conductor — whether a millimetre-wide PCB trace, a package busbar or a sub-micron on-chip wire — has to satisfy two independent constraints, and getting one right while missing the other is a classic failure. The first is electrical: the resistance, set by resistivity times length over cross-sectional area, drops voltage the load needed and burns power as I²R heat. The second is reliability: the current density, current per unit area, must stay below the metal's electromigration limit or the wire physically degrades and eventually fails.

These two constraints push on different dimensions. Voltage drop cares about total resistance, so it's helped by short, wide, thick, copper conductors. Electromigration cares only about current per area, so it's helped by more cross-section regardless of length. A short thin wire might pass the voltage-drop budget easily yet exceed the electromigration limit; a long fat one might be electromigration-safe but drop too much voltage. A sound design checks both, which is why this console reports the drop, the I²R loss and the current density against the limit together.

Material is the other lever, and it's why the industry made a historic switch. Copper has both lower resistivity than aluminium — less drop for the same geometry — and higher electromigration tolerance — more current per area before failure. As wires scaled thinner and currents rose, aluminium ran out of headroom on both counts, and copper interconnect (with diffusion barriers) took over. Selecting the material here shows both effects at once.

This tool analyzes one conductor in detail. The full power path is a network of many conductors plus planes, vias and decoupling, characterized by an overall target impedance — size and screen individual conductors here, then assemble the system view in the Power Delivery Network console, and remember the I²R loss feeds the thermal budget.