A temperature sensor with a 3 sigma inaccuracy of ±2°C without trimming from −50°C to 150°C in a 16nm FinFET process

Abstract

Two compact thermal sensors in advanced technologies are compared. One uses a 20nm planar process, while the other uses a 16nm FinFET process. Both produce a digital temperature reading through the ratiometric conversion of a temperature-dependent and a temperature-independent current. The currents are integrated on an on-chip capacitor, which forms part of a single-bit first-order continuous-time JA modulator. As a result, the modulator does not require an extra op-amp and is insensitive to process variations. The 20nm design dissipates 1.1mW, occupies 0.018 mm2 and achieves a total temperature error of +2.5°C from -25°C to 125°C using a one-point trim. For extra accuracy, the 16nm design uses Dynamic Element Matching. Realized completely with FinFET transistors, it dissipates 1.21mW, occupies 0.0126 mm2 and achieves a total error of +2°C from -50°C to 150°C without any trim.