Fully Differential Operational Transconductance Amplifiers (OTAs)

Abstract

An amplifier is often a fundamental building block of an analog circuit. Fully differential circuits are widely used due to their large available signal swing, and superior supply and substrate interference immunity. In this chapter we will develop the design of fully differential amplifiers, which will be primary building blocks for subsequent designs at a 0.5 V supply voltage. As discussed earlier in Section 1.1, the realization of a low output impedance is required for the implementation of an operational amplifier. The unavailability of the common-drain stage, as seen in Fig. 1.3(b), makes this difficult, and hence we will only discuss the implementation of operational transconductance amplifiers (OTAs).