A 184.8dB-FoMs 1.6MS/s Incremental Noise-Shaping Pipeline ADC with Single-Amplification-Based kT/C Noise Cancellation Technique

The incremental zoom ADC, integrating a low-power SAR quantizer with a high-resolution $\Delta \Sigma$ modulator, is favored for sensor nodes demanding high accuracy, good energy efficiency, and easy system integration. Conventional zoom ADCs, constrained by the low quantization levels of $\Delta \Sigma$ modulators, require extensive conversion cycles for the desired resolution, consequently restricting the conversion speed to several tens of $\text{kHz}$ [1]–[6]. To improve the conversion speed, recent development incorporates the emerging NS-SAR quantizer as the fine stage. Thanks to the highly efficient multi-bit SAR quantization, the required conversion cycle is largely reduced, realizing a boosted speed of $300\text{kS}/\mathrm{s}$ [7]. However, the reduced OSR deteriorates the sampling noise issue due to insufficient averaging. Although $\text{kT}/\mathrm{C}$ noise cancellation can be performed to reduce its impact, the facilitating amplifier must remain active throughout the entire fine conversion phase. This necessitates the use of either a static amplifier [8] or a repeatedly triggered dynamic one [7], both raising substantial power and time consumption. This amplification cost becomes excessive for high-precision noise-shaping ADCs requiring large conversion cycles. Besides, the coarse and fine quantizers of conventional zoom ADCs operate sequentially, limiting its conversion speed. The dynamic zoom architecture supports concurrent coarse and fine conversions; however, it requires repeated sampling and coarse quantization [3]–[5], limiting further performance boost. As a result, current incremental ADCs still face difficulties realizing high speed and good energy efficiency simultaneously.