A switched current, switched capacitor temperature sensor in 0.6u CMOS

A Temperature to Digital Converter is described which uses a Sensor based on the principle of switching accurately scaled currents in the parasitic substrate PNP in a standard fine-line CMOS process. The resulting PTAT δVBEsignal is amplified in an Auto-Zeroed Switched-Capacitor circuit, sampled and converted to a Digital output by a low power 10 Bit ADC providing a resolution of 0.25 degree from -55 to 125 degrees with an error of less than 1 degree. The paper will focus on the design of the Sensor.