A New Low Distortion Analog Multiplier

Abstract

A new method has been proposed to reduce the mobility degradation effect on square-law characteristic of the MOS transistor. This method has been applied to an analog multiplier to form a new low distortion multiplier circuit. This analog multiplier operates with ± 5V power supply. The operating range for each input is ± 3V. In this operating range the nonlinearity for Vx is 0.6% and for Vy is 0.5%. The 3dB bandwidth is specified for Vx as 33MHz and for Vy as 34MHz, respectively. I. INTRODUCTIONAnalog multipliers are the key elements of signal processing circuits. There are several techniques of implementing four quadrant multipliers including techniques based on square-law characteristic of the MOS transistor operating in the saturation region. Several second order effects influencing the linearity of multiplier circuits are reported in the literature [1][2][3][4][5][6][7]. Mobility degradation caused by short channel effect is the most important factor which degrades the linearity of this kind of multipliers. Althought there are several analog multipler circuits [1][2][3][4][5][6][7] based on squarelaw characteristic of MOS transistor, in none of them any special precaution has been introduced to reduce the short channel effect. In this work a new method has been proposed for reducing the mobility degradation effect on square-law characteristic of the MOS transistor. This method has been applied to an analog multiplier [1] to form a new low distortion multiplier circuit. This analog multiplier operates with ± 5V power supply. The operating range for each input is ± 3V. In this operating range the nonlinearity for Vx is 0.6% and for Vy is 0.5%. The 3dB bandwidth is specified for Vx as 33MHz and for Vy as 34MHz, respectively.

Analog Multipliers-Based Double Output Voltage Phase Detector for Low-Frequency Demodulation of Frequency Modulated Signals

“…The analysis of the features of solutions [12]- [46], presented in Table I, gives the following conclusions: a) many circuits are not directly suitable for voltage-mode and mixed mode applications because they have insufficiently low impedance of current input terminals [12]- [17], [19]- [24], [27], [28], [32], [35]- [37], [40], [41], [43]- [45], b) voltage input terminals are available in limited number of cases [18], [26], [29]- [31], [33], [34], [38], [39], [42], [46], c) many circuits process only very low-level signals (dynamical limitation) unsuitable for many purposes (especially [13], [17], [23], [38]), in other words only [31] and [46] are acceptable for our purposes but another features are not fulfilled or significant enhancement is required), d) all solutions in Table I have only one single output and, e) the value of output resistance is not known as well as information about its variability when the input levels of the multiplier are changed or DC voltage is connected to selected pair of input terminals in order to operate as operational transconductance amplifier (independence on driving process [47]).…”

Novel high-precision current-mode multiplier/divider

“…Actually drain current expression includes effects of W, L and V DS on effective threshold, velocity saturation effects, effective mobility dependence on normal field and channel length modulation. Especially, the short-channel effects become more important in MOS transistors at channel lengths of about 1 lm or less and require modifications to the MOS models as well as the circuits that are designed using these MOS transistors [17][18][19].…”