Abstract: A high-speed lookup table is designed using Rapid Single Flux Quantum (RSFQ) logic elements and fabricated using superconducting integrated circuits. The lookup table is composed of an address decoder and a programmable read-only memory array (PROM). The memory array has rapid parallel pipelined readout and slower serial reprogramming of memory contents. The memory cells are constructed using standard non-destructive reset-set flip-flops (RSN cells) and data flip-flops (DFF cells). An n-bit address decoder is implemented in the same technology and closely integrated with the memory array to achieve high-speed operation as a lookup table. The circuit architecture is scalable to large two-dimensional data arrays.

Abstract: Superconducting-semiconducting hybrid memories are disclosed. These superconducting-semiconducting hybrid memories utilize semiconductor circuits to store information, and either superconducting or semiconducting or combinations of superconducting and semiconducting circuits, with at least some superconducting circuitry used, to write and read information. The state of memory cells in the hybrid memories is determined by utilizing superconductor current sensing schemes to detect currents in the bit-line, thereby avoiding any bit-line charging delays and other problems associated with purely semiconductor memories. Additional features of the superconducting-semiconducting hybrid memories include wide margins, dense packing of memory cells, low power dissipation and fast access times. Interface curcuitry for converting superconducting signals to signals compatible with semiconductor circuits and for converting semiconductor signals to signals compatible with superconducting circuits is also disclosed.