Design Of10-bit Sigma-Delta ADC For RFID Temp-sensor Tags Application

Radio Frequecy Identification (RFID) technology, which springed up in the90s of20th century, is an automatic identification technology, and it is the main technology forthe Internet of Things. RFID tag has many advantages, such as smaller size, longerdistance of operation, faster writing and reading speed, multi-card identification, mobileidentification, longer life, it could work in a much harsher environments, resusable anddurable, etc. Because of these advantiges, it is widely used in production, retail,transportation and logistics industry. In recent years, RFID technology has become moresophisticatied. Many products are mature, such as bus cards, and ID cards, etc. However,the application of RFID combined with wireless sensor networks still has manyproblems, and it becomes a research hotspot of RFID technology. In the cases ofcold-chain logistics and other harsh environment, RFID temperature-sensing technologycould be used to reduce manpower, costs, or solves many other problems.Sigma-Delta Analog-to-Digital Converter (ADC) turns the analog signal to digitalsignal by using oversampling and Sigma-Delta modulation techniques. Sigma-Delta’shigh accuracy and low-fequency characteristics make it suitable for the application oftemperature sensors. RFID tags have low power consumption and small areacharacteristics, so this paper attempts to adopt a low-cost, low-power and10-bitSigma-Delta ADC. And in this paper, the major research is the Sigma-Delta Modulaterin Sigma-Delta ADC.In this thesis, we use0.18μm CMOS technology to design a second-orderSigma-Delta Modulator. Supplied with1.5V, the power consumption of the modulator isabout16μw, the layout area of the Sigma-Delta Modulator is175μmx95μm, and theENOB is larger than10-bit.