Low-Power Deep Sub-Micron CMOS Logic e-bog

1. 1 Power-dissipation trends in CMOS circuits Shrinking device geometry, growing chip area and increased data-processing speed performance are technological trends in the integrated circuit industry to enlarge chip functionality. Already in 1965 Gordon Moore predicted that the total number of devices on a chip would double every year until the 1970s and every 24 months in the 1980s. This prediction is widely known as "e;Moore's Law"e; and eventually culminated in the Semiconductor Industry Association (SIA) technology road map [1]. The SIA road map has been a guide for the in- dustry leading them to continued wafer and die size growth, increased transistor density and operating frequencies, and defect density reduction. To mention a few numbers; the die size increased 7% per year, the smallest feature sizes decreased 30% and the operating frequencies doubled every two years. As a consequence of these trends both the number of transistors and the power dissi- pation per unit area increase. In the near future the maximum power dissipation per unit area will be reached. Down-scaling of the supply voltage is not only the most effective way to reduce power dissipation in general it also is a necessary precondition to ensure device reliability by reducing electrical fields and device temperature, to prevent device degradation. A draw-back of this solution is an increased signal propa- gation delay, which results in a lower data-processing speed performance.