A 280 μW Dynamic Zoom ADC With 120 dB DR 118 dB SNDR in 1 kHz BW

Abstract

This paper presents a dynamic zoom analog-to-digital converter for use in low-bandwidth (<1 kHz) instrumentation applications. It employs a high-speed asynchronous successive approximation register (SAR) ADC that dynamically updates the references of a fully differential Δ Σ ADC. Compared to previous zoom ADCs, faster reference updates relax the loop filter requirements, thus allowing the adoption of energy-efficient amplifiers. Fabricated in a 0.16-μm CMOS process, the prototype occupies 0.26 mm² and achieves 119.1-dB peak signal-to-noise ratio (SNR), 118.1-dB peak signal-to-noise-and-distortion-ratio (SNDR), and 120.3-dB dynamic range (DR) in a 1-kHz bandwidth while consuming 280 μW. This results in a Schreier figure of merit (FoM) of 185.8 dB.