Integrated sensor interface circuits require power-efficient high-accuracy data converters. Incremental A/D converters (IADCs) are often the best choice for these, since they can provide excellent energy efficiency, and are easily multiplexed, need only simple digital filtering, and allow low latency. By performing the conversion in multiple steps, the hardware can also be multiplexed among all steps. In this paper, the past, present and anticipated future of IADCs are described. The focus is on multi-step converters.