Multi-Step Switching Methods for SAR ADCs

This paper presents multi-step capacitor switching methods for SAR ADCs based on precharge with floating capacitors and charge sharing. The proposed switching methods further reduce the transient power of the split monotonic switching method (an improved version of the monotonic switching method). Compared to the split monotonic switching, adding charge sharing achieves around 50% reduction in switching power. Using precharge with floating capacitors and charge sharing simultaneously, the switching power reduces around 75%. The proposed switching methods do not require additional intermediate reference voltages.