All CMOS exponential function generator with tunable input and output range

An ultra low-voltage low-power all CMOS exponential function generator is proposed, with tunable input and output ranges. The proposed circuit uses "pre-distortion" technique to extend the dB linear output range. The Taylor series expansion is used for realizing the exponential characteristic. The simulations, based on a 0.25 /spl mu/m CMOS process, show a 25 dB linear output current range at 1.25V supply voltage. The average power consumption is less than 0.1 mW.