%0 Journal Article
%T Recent Subthreshold Design Techniques
%A Mohsen Radfar
%A Kriyang Shah
%A Jugdutt Singh
%J Active and Passive Electronic Components
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/926753
%X Considering the variety of studies that have been reported in low-power designing era, the subthreshold design trend in Very Large Scale Integrated (VLSI) circuits has experienced a significant development in recent years. Growing need for the lowest power consumption has been the primary motivation for increase in research in this area although other goals, such as lowest energy delay production, have also been achieved through sub-threshold design. There are, however, few extensive studies that provide a comprehensive design insight to catch up with the rapid pace and large-scale implementations of sub-threshold digital design methodology. This paper presents a complete review of recent studies in this field and explores all aspects of sub-threshold design methodology. Moreover, near-threshold design and low-power pipelining are also considered to provide a general review of sub-threshold applications. At the end, a discussion about future directions in ultralow-power design is also included. 1. Introduction Subthreshold digital circuits are now well known to ultralow-power designers and have frequently and successfully been used for applications such as implanted sensors and mobile peripheral processors. However, performance degradation and high sensitivity to Process/Voltage/Temperature (PVT) variations are the primary challenges that have confined subthreshold circuit implementations to low-activity applications. There are many recent review papers covering the subjects of sub/near-threshold digital design and their challenges. The goal of this review, however, is to cover a boarder range of designs, to show the interrelation of different solutions for low-power digital design and review the recent updates and new advances in ultralow-power era. Some of useful and comprehensive reviews are as follows. Authors in [1] presented a detailed review that discussed the advantages/disadvantages of subthreshold design, and mathematical equations required for the subthreshold circuits. The paper also covered variation problems briefly and presented subthreshold design techniques for Static Random Access Memories (SRAM) design followed by design techniques for multiprocessing. These discussions make [1] one of the most inclusive early papers. In [2] authors have focused on variations and leakage reduction, to a greater extent, and besides DC-DC converters have also been discussed. In one of the recent reviews, authors (see [3]) presented a detailed review of subthreshold design by exploring subthreshold modelling methods, a few leakage reduction techniques, a
%U http://www.hindawi.com/journals/apec/2012/926753/