A 2+1 multi-bit incremental architecture using Smart-DEM algorithm

This paper describes a multi-bit third-order incremental analog-to-digital (ADC) architecture and design considerations to achieve 18-bit resolution. The architecture uses multi-bit quantization in order to increase resolution and reduce the output swing of op-amps. The non-linearity due to the mismatch of unity elements of multi-bit DAC is properly compensated for with Smart-DEM algorithm. This 2+1 incremental architecture achieves 18-bit resolution with a 3-bit quantizer. Simulation results verify the target resolution achieved with 61 clock periods despite a large unity element mismatch (3σ = 0.5%).