Performance and power implications of decoupling allocation with power gated domains

Gated power delivery network (PDN) system design requires careful decoupling capacitor allocation between ungated and gated loads. This paper illustrates the pros and cons of ungated and gated capacitors to system performance based on impedance and latency characterization. Solution with only ungated decoupling gives power benefits whereas gated decoupling provides optimized performance but larger latency. Simulations of microprocessor packages are used to illustrate challenges and decision factors.