High-performance swing-enhanced floating inverter amplifier using correlated level shifting technique

An improved swing-enhanced floating-inverter amplifier (SEFIA) using the correlated-level-shifting (CLS) technique is presented, simultaneously achieving both high gain and high output swing. The proposed SEFIA uses a reused capacitor to replace the dynamic biasing capacitor and input coupling capacitor. One of the two reservoir capacitors, which supplies power to the amplifier in the auto-zero phase, is also reused in the level shifting phase. Post-layout simulation results show that in the 180 nm CMOS process; the DC gain remains above 73dB for clock frequencies between 50 kHz to 400 kHz. Compared to conventional FIA with CLS, the proposed SEFIA with a 1.8V supply achieves the 1.54 times output swing increase at a clock frequency of 250 kHz. The CLS technique boosts the DC gain of the proposed SEFIA from 50dB to 74.6dB.