IR Drop

Definition: IR Drop refers to the voltage drop across a power distribution network due to its resistance when current flows through it.

Key Points:

  • ‘I’ represents current, ‘R’ represents resistance
  • Reduces the actual voltage reaching circuit elements
  • More significant in advanced nodes with lower supply voltages

Effects:

  • Decreased circuit performance
  • Increased delay
  • Potential logic failures

Factors Affecting IR Drop:

  • Resistance of power grid
  • Current consumption of circuits
  • Distance from power source
  • Switching activity

Mitigation Techniques:

  • Wider power rails
  • Multiple power pads
  • Decoupling capacitors
  • Optimized floorplanning

Importance:

  • Critical for ensuring correct circuit operation
  • Key consideration in power grid design
  • Impacts overall chip reliability and performance

Proper management of IR Drop is essential for maintaining voltage integrity in VLSI designs.