Abstract—This paper presents a linear Operational Transconductance Amplifier (OTA) that combines two linearization techniques, one with adaptive biasing of differential pairs and second with using of resistive source degeneration. OTA has ±0.9v power supply and consumes 250μw. Improvement of adaptive bias circuit and using class A Bout put stage and CMFB circuit has enhanced the CMRR to 169dB in DC that reduces to 131dB at 1MHz. OTA has been simulated with TSMC 0.18μm CMOS technology in Hspice. The simulated third order harmonic distortion (HD3) with applying a 600mvP-P differential input is -65dB at 1MHz frequency.
Index Terms—Operational Transconductance Amplifier(OTA); linearity; adaptive bias circuit; source degeneration; CMRR
Seyed Javad Azhari is with department of Electronics/Electronics Research Center, Iran University of Science and Technology, Tehran, Iran (email: azhari@iust.ac.ir).
Farzan Rezaei is with department of Electronics/Electronics Research Center Iran University of Science and Technology, Tehran, Iran (email: rezaei_farzan@ieee.org).
Cite: Seyed Javad Azhari and Farzan Rezaei, "High linear, High CMRR, Low Power OTA with Class AB Output Stage," International Journal of Computer Theory and Engineering vol. 2, no. 4, pp. 473-477, 2010.
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