A 0.35μm CMOS 1.8V low-power 175MHz variable gain amplifier

A low-voltage intermediate-frequency variable gain amplifier (VGA) is proposed in this paper. The proposed circuit is based on a multiplier cell that has been improved to obtain higher linearity. Simulated in CMOS 0.35 mum technology, the VGA consumes 1.5 mA at a single 1.8 V supply. It shows a continuous gain setting from -18 up to 18 dB with a linearity error below 1 dB and an almost constant bandwidth above 175 MHz. Distortion levels (IM3) are below -70 dB at 10 MHz for a 0.4 Vp-p differential output.