.90 Db, Sigma-delta Modulator

Analog to Digital converter is widely used in all aspects with the development of digital technology and communications. In the field of audio signal processing, analog to digital conversion circuit also played an important role.In this paper, we design a 90dB Sigma-Delta modulator, for audio ADC. It is use SMIC 0.13μm process. From analysis of the spec, determine the structure of the circuit, to completion of the tape out, packaging and testing, we have successfully completed the design and development of the Sigma-Delta modulator.The circuit has many blocks, such as integrator circuit, comparator circuit, reference voltage circuit, clock generator circuit, sample and hold circuit. For each circuit, we have theoretical calculations and analysis, simulation and completed the layout. Finally, we test the chip and get the conclusion.