Ultra Low-Voltage Current Squaring and Multiplier

This paper presents the designs of analog CMOS current squaring circuit and four-quadrant multiplier which are capable for operation under ultra-low supply voltage. The design approach is based on CMOS devices operated in the weak inversion and on its exponential I/V characteristic. Both circuits employ the ultra-low supply voltage of 0.5V and achieve very low static power consumption. The constant gain bandwidth is about 0.1MHz for both circuits. Total harmonic distortion at 100kHz is −52dB and −36dB with power consumption $13\boldsymbol{\mu}\mathbf{W}$ and $18\boldsymbol{\mu}\mathbf{W}$ for the squarer and multiplier, respectively. Theirs performances were verified by simulations using transistor's models of standard $0.18\boldsymbol{\mu}\mathbf{m}$ CMOS process.