Sub-1 V supply nano-watt MOSFET-only threshold voltage extractor circuit

This work presents a self-biased MOSFET threshold voltage VT0 extractor circuit. Its working principle is based on a current-voltage relationship derived from a continuous physical model. The model is valid for any operating condition, from weak to strong inversion, and under triode or saturation regimes. The circuit is MOSFET-only (can be implemented in any standard digital process), and it operates with a power supply of less than 1 V, consuming tenths of nW. Post-layout simulation results show that the extracted VT0 has an error inferior to 1.3%, when compared to the theoretical value, for a -40 to 125°C temperature range. We present variability results from Monte Carlo simulations that support the extracting behavior of the circuit with good accuracy. The occupied silicon area is 0.0076 mm2 in a 0.13μm CMOS process.