A 180µW Dynamic Zoom ADC With 110 dB SNDR in 2 kHz BW

A dynamic zoom analog-to-digital converter(ADC) used in low-voltage and low-power sensor applications related to the Internet of Things(IoT) is presented in this paper. It employs a coarse 5-bit asynchronous successive approximation register(SAR) ADC and a fine second-order delta-sigma modulater(Δ ∑ M). The SAR ADC dynamically updates the references of Δ ∑ M that reduces the loop filter requirements. A low-voltage operational transconductance amplifier(OTA) and a low-power comparator are used in the dynamic zoom ADC. Designed in a 65nm CMOS process, the layout occupies 0.47mm
²
. It achieves 110-dB signal-to-noise-and-distortion-ratio(SNDR) in 2-kHz bandwidth(BW), while only consuming 180µW from a 1.1-V supply. This achieves a Schreier figure of merit(FoM) of 181 dB.