A Data Weight Averaging-Inspired Digital Calibration Method for a 10-Bit Noise-Shaping Successive Approximation Register

This paper presents a digital calibration method for a 10-bit noise-shaping Successive Approximation Register Analog to Digital Converter (SAR ADC). The proposed calibration method is inspired by its Data Weight Averaging (DWA) counterpart, but stays static, while achieving a similar Integral Nonlinearity (INL) and 1.3 dB better Signal-to-Noise Ratio (SNR) in measurements without oversampling. This advantage in SNR holds until an Oversampling Ratio (OSR) of 2 for the proposed method, which also saves 50 % power. At a 1.2 V power supply, the ADC consumes a power of 70 & mu;W at a conversion rate of 50 kHz. Fabricated using 55 nm Complementary Metal Oxide Semiconductor (CMOS) Metal-Oxide-Metal Capacitor (MOMCAP) technology, it occupies an active area of 370 & mu;m x 350 & mu;m, when achieving an INL of 0.3 Least Significant Bit (LSB) and an SNR of 66.9 dB at an OSR of 8.

Automated summary

This paper presents a digital calibration method for a 10-bit noise-shaping SAR ADC. The proposed method achieves a similar INL and 1.3 dB better SNR compared to the traditional DWA method without oversampling. It also saves 50% power and occupies a small active area in the fabrication process.