A broadband linear-in-dB variable-gain amplifier (VGA) circuit is implemented in 0.18 ????m SiGe BiCMOS process. The VGA\ncomprises two cascaded variable-gain core, in which a hybrid current-steering current gain cell is inserted in the Cherry-Hooper\namplifier to maintain a broad bandwidth while covering a wide gain range. Postlayout simulation results confirmthat the proposed\ncircuit achieves a 2GHz 3-dB bandwidth with wide linear-in-dB gain tuning range from ?19 dB up to 61 dB.The amplifier offers a\ncompetitive gain bandwidth product of 2805GHz at the maximum gain for a 110-GHz f???? BiCMOS technology. The amplifier core\nconsumes 31mWfrom a 3.3V supply and occupies active area of 280 ????m by 140????m.
Loading....