A 49-dB continuous linear-in-dB IF VGA technique

A two-stage differential-ramp based continuous-tuning IF VGA is introduced. The design has a bandwidth in excess of 100 MHz consuming 5-mA from a 1.2-V supply. The ramp generation circuit consumes additional 200 muA from a 2.5-V supply. Thanks to the multiple differential control ramps, 49-dB linear-in-dB continuous gain tuning range is achieved with 19-dBm OIP3 at the maximum gain setting. The input referred noise density of the proposed design at maximum gain setting of 40-dB is 3.5-nV/sqrt(Hz).