New BSFQ Circuit Designs with Wide Margins

Recently we have proposed novel Boolean Single-Flux-Quantum (BSFQ) circuits, which just like CMOS circuits support Boolean primitives directly, and do not require local synchronization for each operation cell. However, previous BSFQ AND, OR, and XOR cells suffered from problems with narrow margin, where their critical margins hardly exceeded +lo% due to low flux gain. Furthermore, while being suitable for combinational circuits, previous BSFQ NOT cells had initialization problems in sequential circuits. In this paper, new versions of these circuits with simulated margins beyond 430% are proposed. Moreover, a Muller C-element, an error canceller, a destructive read-out (DRO), and a demultiplexer are also newly created. The operation time, parameter margins, and circuit size of these BSFQ cells are comparable to those of the conventional RSFQ cells.