30GHz Operation of Single-Flux-Quantum Arithmetic Logic Unit Implemented by Using Dynamically Reconfigurable Gates

2016 IEICE transactions on electronics  
A single-flux-quantum (SFQ) arithmetic logic unit (ALU) was designed and tested to evaluate the effectiveness of introducing dynamically reconfigurable logic gates in the design of a superconducting logic circuit. We designed and tested a bit-serial SFQ ALU that can perform six arithmetic/logic functions by using a dynamically reconfigurable AND/OR gate. To ensure stable operation of the ALU, we improved the operating margin of the SFQ AND/OR gate by employing a partially shielded structure
more » ... elded structure where the circuit is partially surrounded by under-and over-ground layers to reduce parasitic inductances. Owing to the introduction of the partially shielded structure, the operating margin of the dynamically reconfigurable AND/OR gate can be improved without increasing the circuit area. This ALU can be designed with a smaller circuit area compared with the conventional ALU by using the dynamically reconfigurable AND/OR gate. We implemented the SFQ ALU using the AIST 2.5 kA/cm 2 Nb standard process 2. We confirmed high-speed operation and correct reconfiguration of the SFQ ALU by a high-speed test. The measured maximum operation frequency was 30 GHz. key words: SFQ circuit, shielding, arithmetic logic unit, reconfigurable logic device
doi:10.1587/transele.e99.c.692 fatcat:ntec3d3yyzghzjybt4ndzjkjgm