Ashok Agarwal,Sachin Rai. “Design of a CMOS Op-Amp and Second Order Sigma Delta Analog to Digital Converter Using 0.18 µ µµ µm CMOS Technology”. International Journal of Research & Technology, vol. 1, no. 1, Mar. 2013, pp. 15-18, https://ijrt.org/j/article/view/6.