A 3.3-V CMOS wideband exponential control variable-gain-amplifier

A CMOS cascadable variable gain amplifier (VGA) with exponential gain control characteristic is presented. The pseudo-exponential gain control function is realized by a source-coupled pair with diode-connected loads. It is suitable for low supply and high speed applications. Using 0.5 /spl mu/m CMOS technology, experimental results show the bandwidth of the proposed amplifier is larger than 150 MHz with a gain control range of 15 dB. The power consumption is 12.5 mW from a 3.3-V power supply.