Design and Simulation of Second Order Sigma-Delta Modulator with Very High Precision and Low Power Consumption for Medical Applications

In this paper, a second order sigma delta modulator is presented that is suitable for medical applications. Using the amplifier and comparator circuits with low power consumption, which are utilized in integrator and comparator, respectively, the power consumption of this modulator has significantly decreased; as one of essential requirements for medical devices. SNDR of the proposed modulator is obtained 102.44 dB which is equal to 16.72 bit implying a high accurate structure. System level analysis and circuit level simulation of the modulator are performed at Matlab and Cadence software, respectively. 180nm CMOS technology is utilized for simulation of the circuit. Comparing the proposed Sigma-Delta modulator with similar works reveals the superior performance of this proposed architecture considering the power consumption and accuracy. In order to accomplish a comprehensive comparison and achieve an overall insight into the performance of the circuit a figure of merit (FOM) is presented including modulator's total power consumption, effective number of bits and bandwidth.