CMOS multiplier design using the differential difference amplifier

This paper presents design techniques for a wide range CMOS differential difference amplifier (DDA) and discusses its application as a basic block in the implementation of four-quadrant multipliers and amplitude modulators, which are widely used in analog signal processing. The DDA can be reconfigured as an op amp, and makes use of the op amp-based multipliers, which are well-developed. In addition, it can be shown that the DDA can be implemented as an AM circuit using only a transistor and a resistor. Experimental results obtained from a 2 /spl mu/m CMOS MOSIS chip are given.<>