Sub-volt fully balanced differential difference amplifier

Abstract

This paper presents a new CMOS structure for a fully balanced differential difference amplifier (FB-DDA) designed to operate from a sub-volt supply. This structure employs the bulk-driven quasi-floating-gate (BD-QFG) technique to achieve the capability of an ultra-low voltage operation and an extended input voltage range. The proposed BD-QFG FB-DDA is suitable for ultra-low-voltage low-power applications. The circuit is designed with a single supply of 0.5 V and consumes only 357 nW of power. The proposed circuit was simulated in a 0.18-μm TSMC CMOS technology and the simulation results prove its functionality and attractive parameters. An application example of a state variable filter is also presented to confirm the usefulness of the proposed BD-QFG FB-DDA.