The high-order \Sigma-\Delta modulator is an appropriate approach for high-bandwidth, high-resolution A/D conversion. However, non-ideal effects such as the finite opamp gain and the capacitor mismatch have great impacts on its performance at a low oversampling ratio. To achieve greater performance under the inevitable non-ideal effects, we explore several multiple-bit schemes, based on our CIQE high-order \Sigma-\Delta architecture, to remove the non-ideal deterioration. Design rules of these multiple-bit schemes are developed and verified by extensive simulations. I. Introduction The A/D converter is an important element for digitalsignal processing systems. The cruxes of an A/D converter are high resolution for precise representation of the original signal and high bandwidth for fast processing. Conventional A/D architectures, e.g., flash, 2-step flash, and successive approximation, are not suitable for highresolution applications because of the need of near-ideal analog component...