366-kS/s 1.09-nJ 0.0013-mm(2) Frequency-to-Digital Converter Based CMOS Temperature Sensor Utilizing Multiphase Clock

Abstract

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 V-DD operation. After one point calibration, the chip-to-chip spread is +2.7 similar to -2.9 degrees C over the temperature range of -40 degrees C to 110 degrees C.