A High-Linearity, 60-dB Variable Gain Amplicier with Dual DC-Offset Cancellation for UWB Systems

A fully differential variable gain amplifier (VGA) for ultra-wideband (UWB) systems has been designed in a standard 0.18 mum CMOS process. The VGA is implemented using three variable gain stages followed by a fixed gain amplifier stage with a dual feedback DC-offset cancellation network to correct DC-offset. The proposed VGA shows a high linear gain range of 60 dB (0.7 dB-60.7 dB) at 650 MHz, drawing 8.9 mA with a 1.8 V power supply. The VGA chip occupies only 0.23 mm
²
(0.47 mmtimes0.47 mm) active area.