Harmonic distortion in high-speed differential A/D converters

The brief discusses the harmonic distortion introduced by the differential input adapter commonly used in flash and folding A/D converters operating without sample and hold. A distributed model of the adapter is proposed, which provides physical insight and allows quantitative evaluation. Moreover, a technique based on a feedforward compensation is presented. It provides a significant reduction of the harmonic distortion with a small increase of the die area.