The subthreshold region of operation has simple physics which allows for a balanced-force approach to behavioral modeling that has shown to be robust to temperature, and a model that encapsulates MOSFET behavior across all operational regions has been developed. The subthreshold region of operation also allows for injection of charge onto floating nodes that allows for persistent storage that can be used in a variety of applications. The combination of charge storage and device modeling has allowed for the development of programmable circuits for digital applications.