A 35-dBm OIP3 CMOS Constant Bandwidth PGA With Extended Input Range and Improved Common-Mode Rejection

An improved CMOS second generation current conveyor with adaptive control circuit (ACC) is proposed, and is used to build a highly linear transconductance-transimpedance programmable gain amplifier (PGA). This PGA is fabricated in a 0.18-μm CMOS technology and draws a 0.58-mA current from a supply of 1.8 V. It achieves a 0-14-dB-gain range within a roughly constant bandwidth of 30 MHz when driving a capacitor load of 2 pF. Enhanced linearity, extended input range, and improved common-mode rejection are achieved due to the employ of the proposed ACC. In addition, gain peaking is less prone to appear as the proposed ACC contributes a significant reduction in X terminal parasitic capacitance.