A 0.5V 723nW 84.3dB-SNDR Dynamic Zoom ADC with CLS-Assisted Capacitively-Biased FIA

This work proposes a floating-inverter-amplifier (FIA) based high-precision dynamic zoom ADC for low-voltage battery-powered applications. A capacitive biasing technique is proposed to reboot the FIA under low voltages, which enables the FIA to operate under a near-threshold supply voltage. Furthermore, correlated-level-shifting (CLS) is employed to boost the DC gain of the FIA to 51 dB. Simulated in 55nm CMOS under a 0.5V supply, the zoom ADC achieves 84.3dB SNDR while only consuming 723nW at a signal bandwidth of 1kHz. This corresponds to a state-of-the-art Schreier figure-of-merit (FoM) of 175.7 dB.