A WIDE-RANGE DIFFERENTIAL-DIFFERENCE AMPLIFIER - A BASIC BLOCK FOR ANALOG SIGNAL-PROCESSING IN MOS TECHNOLOGY

This paper presents a CMOS implementation of a wide input range differ ential difference amplifier (DDA) using a V-I converter with large sig nal handling capability. It introduces the wide range DDA as a basic b uilding block for continuous-time analog signal processing systems. Th e basic features of the DDA are verified experimentally using a 2-mum CMOS process MOSIS chip. The paper shows that it is generally possible to develop DDA-based analog circuits, such as an adder/subtractor and differential integrators, with almost infinite input impedances, low component count and without matching requirements of components/device s external to the DDA. DDA-based circuits such as amplifiers, a MOS gr ounded resistor, four quadrant multipliers and amplitude modulators ar e presented. Such circuits constitute basic building blocks in modern analog VLSI signal and information processing systems. Moreover, the a pplications of the DDA in the implementation of frequency selective ci rcuits, e.g., resonator and state-variable second-order filters are al so given. All proposed circuits and design techniques are experimental ly verified and demonstrate that DDA-based circuits offer a competitiv e design choice to op-amp-based circuits.