A 3.1mW 8b 1.2GS/s single-channel asynchronous SAR ADC with alternate comparators for enhanced speed in 32nm digital SOI CMOS

Abstract

Next-generation digital high-speed links require fast, yet energy-efficient ADCs at minimum area. Recent years saw impressive progress in SAR ADC designs towards higher sampling speed. Asynchronous clocking, redundant capacitive DACs (CDAC), multi-bit decisions per step and interleaved designs have been presented. We present an asynchronous redundant single-channel ADC achieving 1.2GS/s at 1V supply by using two comparators in alternation to relax comparator reset timing. The ADC achieves 39.3dB SNDR and 34fJ/conversion-step with a core chip area of 0.0015mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .