Test implications and challenges in near threshold computing special session

As technology scales deep into nanometer era, power and energy have become major design constraints, especially for energy-harvested and similar ultra-low power systems, such as embedded processors, remote sensors and implantable devices for the Internet of Things (IoT). Aggressive supply voltage scaling is one of the most efficient ways of reducing power and energy for digital circuits. Near-threshold computing (NTC), in which the supply voltage is close to the threshold voltage of the transistor, can provide a very high energy efficiency (10X or higher) compared to the traditional super-threshold region at the cost of significant (>10X) increase in time to complete a task. However, NTC can come with some major challenges such as decreased functional margins in various circuit elements and greatly increased sensitivity to process variations. To ensure correct functionality in the field, testing of NTC circuits faces some serious challenges, and possibly requires a paradigm shift from conventional testing methods.