A PVT-Robust FIA with 60.5 dB DC Gain and 5.2 MHz Bandwidth for Energy-Efficient Switched Capacitor Circuits

Advances in IoT and bioelectronics have heightened the demand for energy-efficient circuit and system designs. The floating inverter amplifier (FIA), with its novel circuit design, high linearity, low noise, and low power consumption, has become a leading solution for implementing switched-capacitor (SC) circuits in ADCs. To address the limited gain of conventional FIAs, this work proposes a cascode-based core module that enhances output impedance, thereby significantly improving gain. Additionally, an optimized split-gate voltage technique is integrated to expand output swing, while a correlated level-shifting (CLS) method further amplifies gain. Simulations confirm a DC gain of 60.3 dB, a unity-gain bandwidth of 5.2 MHz, and power consumption of 14.4 μW at 1.8 V, with robust performance across process, voltage, and temperature (PVT) variations.