A 1.2GHz adaptive floating gate comparator with 13-bit resolution

We present a high-speed voltage comparator that uses floating gate adaptation to achieve high comparison resolution. The comparator uses nonvolatile charge storage for either offset nulling or automatic programming of a desired offset. We exploit the negative feedback functionality of pFET hot-electron injection to achieve fully automatic offset cancellation. The design has been fabricated in a commercially available 0.35μm process. Experimental results confirm the ability to reduce the variance of the comparator offset 3600× and to accurately program a desired offset with maximum observed residue offset of 469μV and standard deviation 199μV. We achieve controlled injection to accurately program the input offset to voltages uniformly distributed from -1V to 1V. The comparator operates at 1.2GHz with a power consumption of 2.97mW.