A low-voltage low-power CMOS V-I converter with rail-to-rail differential input for filtering applications

A low-voltage (/spl les/3 V) low-power CMOS voltage-to-current converter is introduced which has an almost rail-to-rail differential-input swing (/spl plusmn/1.5 V) with a low signal-distortion (/spl les/1%) with a minimum supply voltage of 2 V. The proposed circuit uses class-AB linearization to achieve full-input-swing in the saturation region. In a 1.2 /spl mu/m n-well CMOS process, the 3 dB frequency of the V-I converter is in the range of 113-114 MHz with different biases. The total power consumption is around 0.7 mW. A simple fully-differential 5th-order elliptic filter composed of the proposed V-I converters has THD below 1% with peak-to-peak V/sub out/=1.2 V.