An ultra-low power consumption high-linearity switching scheme for successive approximation register (SAR) analog-to-digital converter (ADC) is presented with a mixed switching method. Based on the combination of C-2C dummy capacitors, the charge sharing technique and monotonic switching method, the proposed switching method achieves high-energy saving and high linearity. Compared with the conventional SAR ADC, the proposed method consumes no reset energy and achieves 98.9% less switching energy and 87.2% reduction in capacitor area. Moreover, the proposed scheme obtains good performance in linearity. Furthermore, the common-mode voltage variation of the proposed scheme is smaller than other published schemes, which is important for decreasing input-dependent offset of the comparator.
Balanced sampling switch for high linearity and a wide temperature range in low power SAR ADCs