A Symmetric Complementary Structure for RF CMOS Analog Squarer and Four-Quadrant Analog Multiplier

Abstract

A symmetric complementary structure for CMOS analog squarer and four-quadrant multiplier is proposed and analyzed. Analog squarer and a four-quadrant analog multiplier by utilizing the square-algebraic identity in the MOS triode region are presented. The squarer has a symmetric complementary configuration of the push-pull source follower and provides high performance in terms of linearity, power consumption, frequency response and total harmonic distortion (THD). The squarer, with −3 dB bandwidth of 1.3 GHz, had a nonlinearity error less than 1% over input signal range of ±1 V. The multiplier is basically constructed by voltage subtractors (for differential function of inputs) and sum-squaring as well as difference-squaring core circuits (for multiplication of two differential inputs signals). The multiplier has a nonlinearity error less than 1% over ±0.5 V input range. The circuit provides a −3 dB bandwidth higher than 1.3 GHz and exhibits a THD lower than 1% with a 1 V peak-to-peak input voltage, which dissipating 2.6 mW. The second-order effects including mismatch effects are discussed. The proposed circuits will be useful in various RF analog signal-processing applications.