A Sub-1μW 16-Bit Fully Dynamic Zoom ADC Compatible With Free-Running and Incremental Modes Using Residue Feedforward and Extended Counting Techniques

This brief proposes a fully dynamic zoom ADC, which uses the residue feedforward technique to reduce the “fuzz” caused by the coarse SAR ADC’s quantization noise leakage in free running mode, and uses the extended counting technique to obtain the quantization error in incremental mode. The zoom ADC achieves high resolution in both modes. An improved cascoded floating-inverter-amplifier based integrator is used for low power and fully dynamic conversion. Fabricated in a standard 180nm CMOS process, the zoom ADC occupies an active area of 0.204mm2, and consumes less than
$1\mu \text{W}$
while achieving 102.1dB and 97.6dB SNDR in 95Hz bandwidth (BW) in free-running and incremental modes, respectively, corresponding to 182.2dB and 177.5dB FoMSNDR.