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A fully deterministic digital background calibration for pipeline ADCs is presented. The proposed approach is based on split ADC concept to give the shortest background calibration time with high accuracy. A slope mismatch averaging technique is employed in a multistage calibration scheme to deterministically detect the circuit errors without any iterative operations or feedback loops, which render it fast and accurate. Analysis and behavioral simulations for the developed multistage calibration demonstrate the efficiency of this technique and its merit over the LMS-based techniques. Practical considerations have been considered and the proposed calibration has been applied on a 200 MS/s 40 nm CMOS split pipeline ADC to correct for the capacitor mismatch and the amplifier finite gain. The post-layout simulation results show a very fast calibration cycle, where the ADC achieves more than 11 ENOB in less than 1600 clock cycles.

International audienceA bottom plate sampling switch sharing technique is proposed to enable split ADC calibration with high frequency inputs for Sample and Hold Amplifier-less (SHA-less) pipeline ADCs. The shared bottom plate switch ensures that both halves of the ADC sample the input at the same time, which restores the calibration accuracy for fast varying inputs without the presence of a front-end SHA, thereby significantly reducing area and power consumption. For further power reduction, a feedforward two stage amplifier has been used to push the speed of the amplifier at lower current consumption and low supply voltage. A 12-bit 200 MS/s pipeline ADC has been designed in 40 nm CMOS technology, and the transistor level simulations of the ADC prove the efficiency of the proposed technique to restore the split ADC calibration accuracy in SHA-less pipeline ADCs

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