366-kS/s 1.09-nJ 0.0013-mm2 Frequency-to-Digital Converter Based CMOS Temperature Sensor Utilizing Multiphase Clock

A smart temperature sensor in 65-nm CMOS, utilizing CMOS ring oscillators, consumes 1.09 nJ at a conversion rate of 366 kS/s. This is achieved by the direct temperature-to-digital conversion method implemented in the frequency-to-digital converter. The algorithm utilized in the fine code generator makes it possible to increase the resolution of the sensor efficiently. Compared to previous work, this brief shows lower VDD operation. After one point calibration, the chip-to-chip spread is +2.7 ~ -2.9°C over the temperature range of -40°C to 110°C.