A Calibration-Free Low-Cost Process-Compensated Temperature Sensor in 130 nm CMOS

A calibration-free low-cost CMOS integrated smart temperature sensor is presented that requires significantly less die area than previously published designs through the use of novel circuit technique and the 130 nm CMOS process. Uncalibrated sensor operation is achieved through the extensive use of analog dynamic element matching and chopper stabilization circuitry. A novel process-compensation circuit is presented that uses the correlation between pinch-base resistance and substrate bipolar V_BE temperature gradient. Accuracy mostly within the range of ±1°C was achieved using a die area of only 0.21 sq. mm. Prototype sensor performance was found to be limited by the low β characteristics of the substrate bipolar transistors implemented in the 130 nm CMOS process.