Sigma-Delta Modulator Design and Analysis for Audio Application

A Sigma-delta modulator is designed in 180nm CMOS process for digital Audio applications. This design is simulated on S-Edit of Tanner EDA tool. In this design continuous time sigma-delta modulator is implemented to reduce the noise problem. This sigma-delta modulator also helps to reduce power consumption of circuit. In these design two stage op-amps is used to implement modulator. Also this design uses second order continuous time modulator for increasing SNR. Circuit design an 11bit low power sigma-delta modulator for digital audio application is given, using a single bit quantizer. The power supply for this circuit is only 1.8v; the modulator achieves 72dB SNR in a 20 KHz BW, while consuming 1mW. Key Words—Analog-to-digital converter (ADC), continuous time, data converter, over sampling, sigma-delta modulation.