A 0–35dB wideband variable gain amplifier in 0.13μm CMOS

A wideband variable gain amplifier (VGA) implemented in 0.13μm CMOS technology is presented. A fixed gain pre-amp with balun function is put in the front, followed by modified Cherry-Hooper amplifiers connected in cascade providing variable gain, which adopting dual loop feedback for bandwidth extension. Negative capacitive neutralization and capacitive source degeneration are employed for Miller effect compensation and DC offset cancellation, respectively. Measurement results show that the proposed VGA achieves 35dB gain tuning range, -29dBm input 1-dB compression point and 9dB noise figure while its upper 3-dB bandwidth is larger than 3GHz. The core VGA consumes 32mW from 1.2V power supply and occupies 0.48mm² area.