A rapid single flux quantum 1 bit arithmetic logic unit constructed with a half-adder cell

• Published in: Superconductor science & technology 2004-06, Vol.17 (6), p.770-774
• Main Authors: Jung, K R, Kim, J Y, Kang, J H, Kirichenko, A F, Park, J H, Hahn, T S
• Format: Article
• Language: English
• ISSN: 0953-2048; 1361-6668
• DOI: 10.1088/0953-2048/17/6/006

We have designed, fabricated, and tested a rapid single flux quantum (RSFQ) 1 bit arithmetic logic unit (ALU) block. The circuit consists of three DC current driven SFQ switches and a half-adder. We successfully tested the half-adder cell at clock frequency up to 20 GHz. The switches were commutating output ports of the half-adder to produce AND, OR, XOR, or ADD functions. For a high-speed test, we attached two switches at the input ports of the half-adder to control the high-speed input data by low-frequency pattern generators. The output in this measurement was an eye-diagram. Using this set-up, the circuit was successfully tested up to 20 GHz. The chip was fabricated using a standard HYPRES 1 kA cm-2 Nb Josephson junction fabrication process.