A single flux quantum standard logic cell library

Abstract:We propose an algorithm of digit-serial adders using single-flux-quantum (SFQ) circuits. The proposed digit-serial adder adapts the carry look-ahead (CLA) adder architecture to generate carry signals, which are generated from the digit-serial data and fed back internally to the following digit-serial data to increase the throughput of the calculation. We have designed and implemented a 4-bit digitserial adder using the SRL 2.5 kA/cm 2 niobium standard process to demonstrate its high-speed operation. The total number of Josephson junctions is 2316. We have successfully tested full operations of the 4-bit digit-serial adder with a bias margin of ±15% at 25 GHz. Its maximum operation frequency was 30 GHz. Keywords: SFQ circuit, superconducting device, josephson junction, digit-serial adder, adder, carry look-ahead adder Classification: Superconducting electronics

Section: Discussionmentioning

confidence: 99%

“…We have designed the 4-bit digit-serial adder with the CONNECT cell library [5] and tested it using on-chip high-speed test systems [6]. The test circuits have been fabricated by using the SRL 2.5 kA/cm 2 niobium standard process [7].…”

Section: Demonstration Of 4-bit Digit-serial Addermentioning

confidence: 99%

Design of fast digit-serial adders using SFQ logic circuits

Park

Yamanashi

Yoshikawa

et al. 2009

“…Physical layouts of the ROM cells were designed with the aid of an inductance extraction program (L-meter [10]) and a circuit parameter optimization program (SCOPE2 [11]). Digital circuits other than the custom-designed ROM cells were constructed using the SFQ digital cell library referred to as the CONNECT library [12]. In measurements, test circuits were cooled at 4.2 K in liquid helium.…”

Section: Methodsmentioning

confidence: 99%

Experimental demonstration of single-flux-quantum sequential-access mask ROM

Mizugaki

Sawada

Watanabe

et al. 2016

We present a superconducting single-flux-quantum (SFQ) mask ROM comprising 2-bit storage cells and a sequential-access driver. Four types of storage cells for 2-bit data ("00," "10," "01," "11") are adopted for reduction of the cell dimensions, whereas the sequential access is suitable for a single-chip quantum voltage waveform generator implemented with an SFQ-based digital-to-analog converter. 2-bit storage cells of 60 × 70 µm 2 are fabricated using a niobium integration technology and tested in liquid helium. Operation of a sequential-access mask ROM with data of 8 bits × 6 words is also demonstrated.

“…The CONNECT top-down design is described here as a typical CAD for the RSFQ circuits. The design is based on the CONNECT cell library [17]. Layouts of all the logic gates are designed in a rectangular shape.…”

Section: Ic Design Technologymentioning

confidence: 99%

Advancement of superconductor digital electronics

Fujimaki

2012

Advancement of superconductor digital electronics, especially Rapid Single Flux Quantum (RSFQ) logic circuit is described. Ultra short pulse of a voltage generated across a Josephson junction and release from charging/discharging process for signal transmission in RSFQ circuits enable us to reduce power consumption and gate delay. The power-delay products (PDPs) of RSFQ integrated circuits (ICs) are 4 or 5 orders of magnitude smaller than those of semiconductor ICs. The fabrication process technology and the related designing technology have been advanced, and RSFQ ICs have been applied to software-defined radio receivers, superconductor detector array systems, and supercomputers. Recently, several kinds of energy-efficient single flux quantum circuit have been proposed to obtain further advantage to semiconductor devices. The PDPs of these circuits become at least 1 order smaller than those of conventional RSFQ circuits. Keywords: single flux quantum, superconductor, energy efficiency, high-speed, power-delay product Classification: Superconducting electronics References