A 1.8-V 73-dB dynamic-range CMOS variable gain amplifier

A linear-in-dB VGA is fabricated in 0.18-/spl mu/m CMOS technology. It is composed of three cascaded VGAs. Each of them is based on a conventional VGA and a proposed gain control circuit. To avoid devices parameters and temperature behaviour on gain characteristics of VGA, a bias circuit is adapted to a proposed gain control circuit. The gain range of 73dB, the gain error of within /spl plusmn/2dB, the NF of 5dB are obtained at 380MHz by measurement, and the maximum current consumption is 6 mA under a single 1.8V power supply.