Patent ID: 10424380

Abstract:
Physically unclonable function (PUF) memory employing static random access memory (SRAM) bit cells with added passive resistance are disclosed. Added passive resistance can enhance imbalance between transistors in the SRAM bit cell for improved PUF output reproducibility. Enhancing transistor imbalance can more fully skew the SRAM bit cell for increased PUF output reproducibility while still achieving the benefits of output randomness. In one exemplary aspect, added passive resistances in the SRAM bit cell are coupled to a drain of one or more pull-down N-type FETs (NFETs)) in one or more cross-coupled inverters in the SRAM bit cell to enhance imbalance between the inverters. Enhanced imbalance between the inverters increases sensitivity in the output voltage of the SRAM bit cell for a given change in input voltage resulting in greater skew of the SRAM bit cell for increased reproducibility.