Sign-Off Requirements for IR-Drop Analysis The target comes from the top level and is typically 10-20% depending on the SOC. A common breakdown is a static IR-drop budget of about 2.5 to 3% of (VDD + VSS), with the dynamic IR-drop budget around three times the static value. KEY Targets come from the top level - roughly 2.5-3% of (VDD+VSS) static, with dynamic about 3x the static budget.

Timing Margins in the IR-Drop Target Yes, IR-drop analysis takes timing information into account. For example, Redhawk uses a timing window file - which carries slew and load information for each pin - as an input to produce more accurate results. KEY Yes - IR-drop tools like Redhawk use a timing window file with per-pin slew and load for more accurate results.

Electromigration Violations in Practice

• For EM on a wire, first try to widen the metal; if that area is congested, move the net to a higher metal layer where there is more room to increase the width.
• For EM on vias, add more vias in parallel to share the current. KEY Fix wire EM by widening metal or promoting to a higher layer; fix via EM by adding parallel vias.

Cell Power in Static vs Vectorless IR Drop Static analysis uses an average-power algorithm and assumes everything is switching, since power is treated as uniformly distributed across the design. Vectorless IR analysis instead uses probability - for example, if the toggle rate is 20%, there is a 20% probability that the cell switches - so the assigned power reflects that activity factor. KEY Static assumes uniform full switching (average power); vectorless assigns power by the cell's toggle-rate probability.