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Title [REGULAR PAPER] A 10-bit, 50-MS/s Cyclic and SAR Combined Two-stage ADC with Gain Error Calibration
Authors Cheonwi Park;Byung-geun Lee
Page pp.585-593
ISSN 1598-1657
Keywords SAR ADC; Cyclic ADC; hybrid; gain error calibration; low voltage operation
Abstract This paper presents a two-stage analog to digital converter (ADC) combined with cyclic and successive approximation register (SAR) architectures. A correlated level sampling (CLS) technique is implemented to reduce the DC gain requirement of the op-amp from 65 dB to 35 dB. Moreover, a capacitor sharing technique is adopted to reduce the size of the op-amp load capacitors. The proposed ADC achieves both low-power consumption and a small chip area by means of the proposed structure. Furthermore, the conversion speed increases by operating both stages simultaneously. The ADC is fabricated using a 110 nm complementary metal-oxide semiconductor (CMOS), and occupies a core area of 0.247 mm2. The signal-to-noise-and-distortion ratio is 56.4 dB with a 2.4-MHz input. It consumes 2.17-mW of power from a 1.2-V supply voltage, and achieves an 80.4 fJ/step of power efficiency.