A Wideband Digital Variable Gain Amplifier with DC Offset Cancellation in SiGe 0.18μm BiCMOS Technology

This paper presents a five-stage wideband digital controlled variable gain amplifier (DVGA). A bandwidth extended technique is proposed in this design to enhance gain flatness and enlarge gain range in high operating frequency. DC offset cancellation in this design helps to enhance the performance of proposed DVGA. The design is simulated using a commercial 0.18 mu m SiGe BiCMOS technology. The DVGA has a simulated gain range of 64.7 dB with a 3-dB bandwidth from 3 MHz to 3.55 GHz, an output 1-dB gain compression point better than -5.2 dBm, an input return loss better than 11.9 dB, an output return loss better than 18 dB, and a dc power consumption for core DVGA circuit of 3.7 mW from a 1.8-V supply.