Robust Ultra-Low Power Subthreshold Logic Flip-Flop Design for Reconfigurable Architectures

Low power consumption and radiation hardness are generally competing requirements for space electronics as well as many Earth-bound high reliability applications. Fault tolerance typically requires redundancy and reconfigurability to ensure correct functional operation in the presence of errors. However, this runs contrary to the requirement for reduced power consumption in many battery-powered applications. Recently, subthreshold logic has emerged as a technology that delivers the theoretical minimum energy per computation by running at ultra-low voltages. For many applications, the resulting performance degradation is tolerable due the dramatic increase in energy efficiency. Beyond the concerns with performance, an additional challenge is related to radiation hardness and noise immunity. The marriage of subthreshold logic and reconfigurable, high-reliability electronics is inevitable, yet there has been to date no investigation of the effects of radiation on circuits that operate at such low voltages. This paper provides a comprehensive comparison of a variety of flip-flop designs at subthreshold levels