0.5–9 GHz CMOS variable gain amplifier with control linearization, low phase variations and self-matching

This article presents the design of a variable gain amplifier (VGA) with a new control circuitry, enabling a linear control of the gain while ensuring input return loss matching. While changing the gain by 47dB, the phase is less than 4°, making this VGA a suitable building block for multi-antenna frontends. The VGA together with the novel control circuitry was implemented in a 180nm CMOS process. The circuit has an active area of 220μm × 110μm and consumes 6.5mA from a 1.8V power supply.