A 700nW Compact Temperature Sensor With a One-Point Trimmed Inaccuracy of +1.2/–1.0 ∘C For On-Chip Thermal Monitoring

Modern high-performance processing chips utilize on-chip temperature sensors to monitor the temperature. In addition to a small area and low power, there is a strong demand for high accuracy with low-cost calibration. This brief presents an accurate sensor that converts the thermal information contained in the current ratio of two subthreshold MOSFETs to duty cycle. The proportional operation ensures that the slope of the linear sensing relationship remains unaffected by process variation, thereby guaranteeing the achievement of one-point trimming. The dynamic slope compensation (DSC) method is proposed to improve sensor supply sensitivity. Implemented in a 0.153-μm CMOS process, the proposed sensor occupies only 1632 μm2 and consumes 0.7 μW at room temperature. The measured inaccuracy is +1.2/–1.0 ∘C (3σC) in –20∘C~120∘C after one-point calibration and systematic error removal. With the assistance of DSC, the sensor can achieve a supply sensitivity of 4.3 ∘C/V.