DESIGN AND OPERATION OF A QUANTUM FLUX PARAMETRON BIT-SLICE ALU

The design of Quantum Flux Parametron (QFP) majority logic circuits pr esents a number of unique constraints. For example, interconnects must be kept short and have a common small inductance. The former suggests that the bit-slice architecture is well suited to QFP circuits. In or der to test this conjecture, a suitably complex logic circuit was desi gned and a small part of it was fabricated. A design for a 16-function bit-slice arithmetic-logic unit (ALU) was found that satisfied the co nstraints. It can compute on n-bit operands in 2n+4 QFP stages. A redu ced version of the bit-slice ALU cell, containing 30 QFP's, was fabric ated and successfully tested at low speed. The design experience showe d that complex combinatorial QFP logic circuits are possible. Larger c ircuits will be feasible with computer-aided tools.