The development of the precise standard cell that can be upset down

It has been proved that most of the standard cells, which are made with special technology and are able to be upset, have the annual variations less than 0.6 /spl mu/V through long-term survey, transportation, upset and all kinds of performance tests. It can rapidly restore the original value after upset down and is suitable to be the transfer voltage standard for the comparison of two different Josephson voltage standards.