A 225 μm ${}^{2}$ Probe Single-Point Calibration Digital Temperature Sensor Using Body-Bias Adjustment in 28 nm FD-SOI CMOS

Abstract

An embedded digital temperature sensor based on a single-ended probe is implemented in a 28 nm fully depleted siliconon-insulator process. The nMOS-only ring-oscillator probe uses singlepoint calibration based on body-bias tuning of its well for process compensation. Nonlinearity compensation is implemented on-chip in custom digital logic, resulting in an area-efficient (225 μm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> per probe, 11 482 μm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> for the full system) sensor while achieving -1.4 °C/ +1.3 °C accuracy using 2.0 nJ/sample and maintaining functionality over a 0.62-1.2 V range, making it suitable for temperature monitoring in digital systems-on-chip.