Design and analysis of ultra low power processors using sub/near-threshold 3D stacked ICs

In this paper, we study a 3D IC micro-controller implemented with sub-threshold supply for ultra-low power applications. Our study is based on GDSII layouts of a sub-threshold 8052 micro-controller that consumes 3.6μW power running at 20 KHz clock frequency and 0.4V logic supply. Our study confirms that sub-threshold circuits indeed offer a few orders of magnitude power vs performance tradeoff. In addition, our 3D sub-threshold design reduces the footprint area by 78% and wirelength by 33% compared with the 2D counterpart. Our studies also show that thermal and IR drop issues are negligible in this sub-threshold 3D implementation due to its extreme low power operation. Lastly, we demonstrate the low power and high memory bandwidth advantages of many-core 3D sub-threshold circuits.