A Wideband Variable-Gain Amplifier with a Negative Exponential Generation in 40-nm CMOS Technology

A wideband variable-gain amplifier (VGA) with a negative exponential generation using 40 nm CMOS technology is reported. By compensating a single-branch negative exponential generator (NEG) which features a composite of dual Taylor series, the proposed negative exponential generation further extends the dB-linear range. The measurement results show the overall VGA achieves a dB-linear range of 51 dB (-34 ~ 17dB) with a gain error less than ± 1 dB. In addition, the bandwidth is around 7 GHz under different gain settings. The core circuit draws 24.6 mA current from a 1.1 V power supply (excluding the output buffer) and occupies an active area of 0.038 mm2.