A 35 dB-linear exponential function generator for VGA and AGC applications

摘要

A new current-mode based exponential function generator with high dB-linear range is developed. The exponential function is based on Taylor's concept. The proposed circuit is composed of current-to-current squarers, current multipliers, and a linear V-I converter with linearization technique. Based on a 0.25 /spl mu/m CMOS process, the simulations show a 35 dB-linear output current range with the linearity error less than 0.5 dB. The power dissipation is less than 0.3 mW at 1.25 V supply voltage.