Abstract—A high-driving class-AB buffer amplifier, which consists of a high-gain input stage and a pair of operational transconductance amplifier, is proposed. This paper presents a novel systematic offset minimization The high-driving capability is mainly provided by the folded amplifier class-AB CMOS operational amplifier. The proposed structure has a replica-gain circuit, generating a dc replica bias to the differential input stage, and providing differential gain as well as level conversion to drive the class- AB output stage .The circuit contains transconductance amplifiers in a rail to rail operation with both input and output stage based on the micro wind technology and the offset due to device mismatch. An op amp low Cmos design is present in this paper. The circuit uses dual transconductance input pairs to achieve a rail-to-rail common mode input voltage range. Special attention has been given to the offset voltage cancellation of the op amps., and the circuit exhibits the settling time of 3 μs, for a voltage swing of 3.3 V under a 560pF capacitance load with a power supply of 5 V. The offset voltage of the amplifier reduced to a very small value of 0.0182mv.The area of this amplifier is 40*70 μm2.
Index Terms—CMOS, multistage amplifiers, class-AB amplifier, signal driver, offset voltage cancellation, , operational transconductance amplifiers (OTAs)
Department of Electronics & Communication Engineering MANIT, Bhopal (Email:ankur.beohar@rediffmail.com).
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Cite: Ankur Beohar and R. K. Baghel, "A Class AB Amplifier with a Reduced Crossover Distortion for Signal Driver,"
International Journal of Engineering and Technology vol. 2, no. 5, pp. 486-490, 2010.
