Digital controlled variable gain amplifier (DVGA) for IF to digital conversion

A Digital controlled Variable Gain Amplifier (DVGA) for IF to digital conversion systems is presented. The amplification ranges from 6 to 30 dB in 6dB steps. The differential amplifier is optimised for low noise, low distortion and fast settling behaviour. In combination with a 12 bit A/D converter, the DVGA increases the dynamic range of the IF to digital conversion system to 100 dB. The proposed DVGA combines low noise of 4nV/sqrt(Hz) with harmonic distortion below -50 dBc for 2Vpp output signal. The device is implemented in a 13 GHz / 1µm BiCMOS technology and consumes about 150mW.