A low-voltage low-power high dB-linear and all CMOS exponential V-I conversion circuit

A very compact, all CMOS, exponential V-I conversion circuit is proposed for low-voltage and low-power applications. The exponential characteristic is based on the Taylor concept. A new technique to improve the dB-linear output current range of the V-I circuit has been introduced. Based on a 0.18 /spl mu/m CMOS process, the measured results show 44 dB of output current range with a very low current consumption of less than 0.18 mA from a 1.2 V supply voltage. The chip size, excluding bond-pads, is 170/spl times/90 /spl mu/m. The proposed circuit can be used for the design of low-voltage, low-power analog and mixed-mode circuits such as variable gain amplifiers (VGA), automatic gain control (AGC), etc.