{"title":"Variable Input Range Continuous-time Switched Current Delta-sigma Analog Digital Converter for RFID CMOS Biosensor Applications","authors":"Boram Kim, Shigeyasu Uno, Kazuo Nakazato","volume":51,"journal":"International Journal of Electronics and Communication Engineering","pagesStart":485,"pagesEnd":490,"ISSN":"1307-6892","URL":"https:\/\/publications.waset.org\/pdf\/2700","abstract":"<p>Continuous-time delta-sigma analog digital converter (ADC) for radio frequency identification (RFID) complementary metal oxide semiconductor (CMOS) biosensor has been reported. This delta-sigma ADC is suitable for digital conversion of biosensor signal because of small process variation, and variable input range. As the input range of continuous-time switched current delta-sigma ADC (Dynamic range : 50 dB) can be limited by using current reference, amplification of biosensor signal is unnecessary. The input range is switched to wide input range mode or narrow input range mode by command of current reference. When the narrow input range mode, the input range becomes &plusmn; 0.8 V. The measured power consumption is 5 mW and chip area is 0.31 mm^2 using 1.2 um standard CMOS process. Additionally, automatic input range detecting system is proposed because of RFID biosensor applications.<\/p>\r\n","references":"[1] L. Luh, J. Choma, and J. Draper, \"A 50 MHz continuous-time switched-current \u03a3\u0394 modulator,\" IEEE Int. Symp. Circuits and Systems., 1998, vol. 1, pp. 579-582.\r\n[2] L. Luh, J. Choma, and J. Draper, \"A continuous-time common-mode feedback circuit (CMFB) for high-impedance current-mode applications,\" IEEE Trans. Circuits and Systems 2, vol. 47, pp. 363-369, 2000.\r\n[3] Y. Yazawa, T. Oonishi, K. Watanabe, R. Nemoto, M. Kamahori, T. Hasebe, and Y. Akamatsu, \"A wireless biosensing chip for DNA detection,\" ISSCC Dig. Tech. Pap., 2005, p. 562.\r\n[4] Y. Yazawa, T. Oonishi, R. Watanabe, R. Nemoto, and A. Shiraishi, \"Radio frequency identificaiton sensor chips with anticollision algorithm for simultaneous detection for multiple DNA targets,\" J. App. Phys., 2010, vol. 49, pp. 04DL13, 2010.\r\n[5] K. Murari, C. Sauer, M. Sanacvic, G. Cauwenberghs, and N. Thakor, \"Wireless multichannel integrated potentiostat for distributed neurotransmitter sensing,\" in Proc. 27th Ann. Int. Conf. IEEE EMBS, 2005, pp. 7329-7332.\r\n[6] C. Ioumazou, F. J. Lidgey, and D. G. Haigh, \"Analog IC design, the current-mode approach,\" IEEE press, 1993.\r\n[7] H. J. oguey, and D. Aebischer, \"CMOS current reference without resistance,\" IEEE Journal of Solid-State Circuits, vol. 32, no. 1, pp. 1132-1135, 1997.","publisher":"World Academy of Science, Engineering and Technology","index":"Open Science Index 51, 2011"}