Development of an ultra-small smart temperature sensor with quartz tuning fork resonators

This paper discusses a smart temperature sensor system that comprises of a high performance quartz tuning fork temperature sensor, interface with CMOS circuitry and control algorithm for reconfiguration. The ideal thermo-sensitive cut for quartz tuning fork resonators is analyzed with the theory, and is optimized by FEM (Finite Element Method). The specific cut quartz tuning fork was fabricated using photolithography and the etching technology. And the tuning fork sensing element (4 x 1 x 0.2mm(3)) is so small that can be housed in the capsule (02 x 6 mm). The smart temperature sensor along with the interface IC to FPGA and special control algorithm may easily realize the sensor reconfiguration and the auto-calibration in the field. The experimental result indicates that the sensitivity of this sensor can reach 65 ppm/degrees C in the temperature range from-20 to 140 degrees C, it guarantees that precision is 0.01 degrees C, the resolution is 0.001 degrees C and the response time is 1s.