A 1.2 GHz 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 0.35 /spl mu/m process. Experimental results confirm the ability to reduce the variance of the comparator offset 3600/spl times/ and to accurately program a desired offset with maximum observed residue offset of 469 /spl mu/V and standard deviation 199 /spl mu/V. We achieve controlled injection to accurately program the input offset to voltages uniformly distributed from -1 V to 1 V. The comparator operates at 1.2 GHz with a power consumption of 2.97 mW.