This paper investigates a new second order, 14-bit resolution, 800nW power consumption sigma-delta modulator which is suitable for biomedical applications. The proposed modulator is designed in the sub-threshold region and used 0.18um TSMC CMOS technology. In this paper, the maximum value of saturation is achieved by using of the coefficients of second order modulator which is approximately 5-DBFS. Moreover, the CDS technique is used to eliminate the flicker noise. Also, the Nyquist-rate, the sampling frequency and the maximum SNDR of the proposed modulator are 100Hz, 12.8 KHz and 86dB, respectively. The proposed structure improves bandwidth frequency, oversampling frequency and time resolution of the sigma-delta modulator.
