The number of input latching comparators in a flash analog-to-digital converter is significantly reduced by merging the input latching function into exclusive OR gates used in the converter's decoding section. A latching exclusive OR gate used for this purpose employs resonant tunneling...http://www.google.com/patents/US5721503?utm_source=gb-gplus-sharePatent US5721503 - Flash analog-to-digital converter with latching exclusive or gates
