Why Area Might Reduce Power in Nanoscale CMOS

In this paper we explore the relationship between power and area. By exploiting parallelism (and thus using more area) one can reduce the switching frequency allowing a reduction in VDD which results in a reduction in power. Under a scaling regime which allows threshold voltage to increase as VDD decreases we find that dynamic and subthreshold power loss in CMOS exhibit a dependence on area proportional to A(σ-3)σ/ while gate leakage power ∝ A(σ-6)σ/, and short circuit power ∝ A(σ-8)σ/. Thus, with the large number of devices at our disposal we can exploit techniques such as spatial computing, tailoring the program directly to the hardware, to overcome the negative effects of scaling. The value of σ describes the effectiveness of the technique for a particular circuit and/or algorithm - for circuits that exhibit a value of σ ≤3, power will be a constant or reducing function of area. We briefly speculate on how σ might be influenced by a move to nanoscale technology.