A 16-bit 16-MS/s SAR ADC With On-Chip Calibration in 55-nm CMOS

This paper presents a successive approximation register (SAR) analog-to-digital converter (ADC) that is much smaller and faster than other recently reported precision (16-bit and beyond) SAR ADCs. 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 using reservoir capacitors to improve speed and reduce area, plus LSB repeats and statistical residue measurement to improve efficiency. The prototype achieves 97.5-dB spurious-free dynamic range at 100-kHz input while operating at 16 MS/s and consumes 16.3 mW. It was fabricated in a 55-nm CMOS process and occupies 0.55 mm(2).