Margin analysis of quantum flux parametron logic gates

An analytical approach is used to estimate the (quasi-static) margins of quantum flux parametron (QFP) logic gates. The operation of a single QFP is analyzed in detail, and input biases or output variations caused by parameter fluctuations are obtained. The results are used to estimate the margins and yields of the QFP logic gates. The relations between the margin and the parameter fluctuations are obtained. The yields are estimated assuming normal distributions of the fluctuations. The calculations are consistent with experiments performed to date. The static margins of the QFP logic gates discussed here are sufficient, with presently available process technology, for medium size integrated circuits