A 16-bit 16MS/s SAR ADC with on-chip calibration in 55nm CMOS

Abstract

This paper presents a SAR ADC that is much smaller and faster than the recently reported precision (16-bit and beyond) SAR ADCs [1, 2, 3]. In addition, it features low input capacitance and an efficient on-chip foreground calibration algorithm to fix bit weight errors. Several other enabling techniques are also used, including signal independent reference switching using reservoir capacitors to improve speed and reduce area, LSB repeats and ADC residue measurement to improve efficiency. The prototype achieves 97.5dB SFDR while operating at 16MS/s and consumes 16.3mW. It was fabricated in 55nm CMOS and occupies 0.55mm2.