Implications of Ultra Low-Voltage Devices on Design Techniques for Controlling Leakage in NanoCMOS Circuits

Enabled by technology scaling, ultra low-voltage devices have now found wide application in modern VLSI circuits. While low-voltage implies reduced dynamic power, it also signifies increased leakage power, as lower supply voltages are usually paired with lower threshold voltages in order to preserve circuit speed. This originates an increase in sub-threshold leakage currents that constitute, today, one of the most serious bottlenecks to further technology and supply voltage scaling. The need of controlling leakage power in nanometric devices is imposing a significant shift in the way integrated circuits are designed and manufactured. The behavior of devices with nanometric feature sizes is much more sensitive to parameters such as the operating temperature of the circuit, which in the past were neglected. In this paper we quantitatively analyze the leakage control capabilities of some well-established circuit-level design techniques, and assess how the effectiveness of such techniques scales with respect to decreased supply voltages (as induced by technology scaling) and temperature variations, thus providing an interesting insight on how leakage control solutions that are in use today is applicable in future designs