Abstract
A high temperature integrated sensor interface is proposed. The sensor interface has a fully differential time domain architecture. This approach offers the advantage of better thermal stability compared to typical analog based architectures. The sensor interface is based on Injections Locked Oscillators (ILO) used as phase shifters. A pair of ILOs converts the sensor output voltage into a phase shift difference which is then digitized using a time to digital converter. The sensor interface output depends only on the ratio of its parameters values rather than their absolute values thus leading to a low temperature dependency. The sensor interface is fabricated using a 0.18µm Partially-Depleted Silicon on Insulator technology (PD-SOI) from XFAB which is chosen for its thermal robustness. Measurements show that the sensor interface achieves a thermal variation of 178ppm/°C over ±60mV input full scale and a thermal variation of 65ppm/°C over ±40mV input full scale over a wide operation temperature range extended from -20°C to 220°C.