High-Speed Demonstration of Bit-Serial Floating-Point Adders and Multipliers Using Single-Flux-Quantum Circuits

We have been developing a large-scale reconfigurable data path (LSRDP) based on single-flux-quantum (SFQ) circuit technology for high-performance computing systems. In the SFQ LSRDP, a large number of SFQ floating-point adders (FPAs) and floating-point multipliers (FPMs) are directly connected to each other through routing networks to reduce a memory access rate. In this paper, we show our recent results about the SFQ FPAs and FPMs. Utilization of the National Institute of Advanced Industrial Science and Technology´s 10-kA/cm² Nb process makes it possible to accelerate the clock frequency to more than 50 GHz. We successfully demonstrated the high-speed operation of single- precision FPAs and FPMs, whose clock frequency is beyond 50 GHz, by on-chip high-speed tests. We estimate the performance and energy efficiency of SFQ FPAs and FPMs based on the designed circuits.