A 1.5 GHz linear-in-dB Variable Gain Amplifier with process and temperature tracking in 0.18-µm CMOS

A linear-in-dB CMOS Variable Gain Amplifier (VGA) targeting large-bandwidth applications, such as a DVD front-end and a Digital TV tuner's RF VGA is implemented in 0.18-µm CMOS. With a novel process and temperature variation tracking scheme and a charge-pump based negative supply to extend tracking range and improve linearity, this VGA provides stable −6 to 16 dB amplification across PVT variations. With less than 3 mA biasing current, the 3-dB bandwidth is more than 1.5 GHz and the THD is less than −45 dB for output swings greater than 500 mVppd.