Work out ir drop in power grid instantly with clear inputs, formula shown and shareable results.
Static IR drop is simply current times grid resistance, but at sub-volt supplies the budget is brutal: 5% of 0.85 V is only 42 mV, so 60 A can tolerate no more than about 0.7 milliohms of grid resistance from the pads to the load.
IR drop
drop = I x R_grid; must stay within the supply tolerance budget along with dynamic droop
The absolute tolerance shrinks with the supply while currents rise, so the allowable grid resistance falls quadratically in effect.
More and wider metal on upper layers, more power vias, more C4 bumps, and placing high-current blocks near the power entry points.