Design and Verification of SFQ Cell Library for Superconducting LSI Digital Circuits

Gao, Xi; Qiao, Qi; Wang, Mingliang; Niu, Minghui; Liu, Huanli; Maezawa, M.; Ren, Jie; Wang, Zhen

doi:10.1109/tasc.2021.3062570

Cited by 18 publications

(6 citation statements)

References 18 publications

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“…We employ the LV-RSFQ and ERSFQ circuits with lower power consumption than the traditional RSFQ circuits. The layout design of both versions is based on the RSFQ cell library of the SIMIT-Nb03 process [16,19]. For the design of LV-RSFQ SQCC, the conversion of RSFQ cells to LV-RSFQ cells can be accomplished by reducing the values of bias resistance and voltage, and the static power dissipation can be reduced in equal proportions [15].…”

Section: Low Power Design and Test Resultsmentioning

confidence: 99%

“…However, the structure of our counter is simpler, and the number of JJs for a counter of counting ranging from 1 to 2 4 is only 44 JJs. As demonstrated in figure 3, our counter consists of several stages of TFFC composed of confluence buffer and TFF [16]. When the SFQ pulse train is applied to the counter through the CIN port, after counting N SFQ pulses, an SFQ pulse is output at the output port COUT, where N could be any number between 1 and N max .…”

Section: Design Of Countermentioning

confidence: 99%

“…We designed the proposed SQCC by selecting the SFQ circuit with lower power consumption than the RSFQ circuit. First, we selected the low-voltage rapid single flux quantum (LV-RSFQ) circuit whose cells are compatible with those in the SIMIT Nb03 RSFQ cell library [15,16]. Then we optimized the design with an energy-efficient rapid single flux quantum (ERSFQ) circuit without static power consumption to further lessen power consumption [2,17,18].…”

Section: Introductionmentioning

confidence: 99%

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Low power single flux quantum qubit control circuit without high-frequency input

Weng

Peng

Ren

2023

Supercond. Sci. Technol.

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The use of high-frequency input signals from room-temperature microwave sources makes it difficult to scale up the number of quantum bits in universal quantum computers. To address this issue, superconducting single flux quantum (SFQ) integrated circuits are being explored as suitable candidates for qubit manipulation in universal quantum computers. This paper deals with a scalable SFQ qubit control circuit (SQCC) structure that requires only low-frequency input. The circuit mainly consists of a pulse generator and a counter, that output the SFQ pulse train with adjustable frequency and a controllable number of pulses, which is applicable to control single-qubit Clifford operations. The design of low-voltage rapid single flux quantum (LV-RSFQ) and Energy-efficient rapid single flux quantum (ERSFQ) for the SQCC achieves low power consumption and provides a basis for scaling up SQCC to control more qubits. The proposed circuits are fabricated under SIMIT-Nb03 process and successfully pass test verification. The achieved test results reveal that the adjustable output frequency ranges of the SQCC based on the LV-RSFQ and ERSFQ designs in order are [2.40, 8.11] GHz and [4.81, 5.14] GHz. In the operating frequency range, the circuit is able to generate the correct number of SFQ pulses under control. The controllable number range is from 1 to 128. When the circuits operate at 5 GHz, the total power consumptions of the above circuits in order are 23.88 μW and 6.2 μW. All input signals are low-frequency signals, which frees the control of large-scale qubits from limitations caused by high-frequency inputs produced by room-temperature microwave sources.

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Section: Low Power Design and Test Resultsmentioning

confidence: 99%

Section: Design Of Countermentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Low power single flux quantum qubit control circuit without high-frequency input

Weng

Peng

Ren

2023

Supercond. Sci. Technol.

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“…The modules of nlm4, nlm5, and lm0 are taped out in different batches by using our self-developed SIMIT Nb03 6-kA/cm2 process. [22,23] The circuits are tested by using the OCTOPUX [24] test system for superconducting integrated circuits. Figure 6 shows the microphotographs of the lowfrequency and high-frequency test circuits of nlm4, and the low-frequency test circuits of lm0 and nlm5.…”

Section: Module Design and Informationmentioning

confidence: 99%

Implementation of an 8-bit bit-slice AES S-box with rapid single flux quantum circuits

et al. 2022

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The Rapid Single Flux Quantum (RSFQ) circuit is a kind of superconducting digital circuit, having the property of a natural gate-level pipelining synchronous sequential circuit, which demonstrates high energy efficiency and high throughput advantage. We found that the high-throughput and high-speed performance of the RSFQ circuits can take the advantage of a hardware implementation of the encryption algorithm, but these are rarely applied to this field. Among the available encryption algorithms, the AES algorithm is an advanced encryption standard algorithm. It is currently the most widely used symmetric cryptography algorithm. In this work, we aim to demonstrate the SubByte operation of an AES-128 algorithm by using RSFQ circuits based on the SIMIT Nb03 process. We design an AES S-box circuit in the RSFQ logic, and compare its operational frequency, power dissipation, and throughput with those of the CMOS-based circuit post-simulated in the same structure. The complete RSFQ S-box circuit costs a total of 42237 Josephson junctions with nearly 130 Gbps throughput under the maximum simulated frequency of 16.28 GHz. Our analysis shows that the frequency and throughput of the RSFQ-based S-box are about four times higher than those of the CMOS-based S-box. Further, we design and fabricate a few typical modules of the S-box. Subsequent measurements demonstrate the correct functioning of the modules in both low and high frequencies up to 28.8 GHz.

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“…The critical current in-tensity of the Josephson junctions is 6 kA/cm 2 . [21] Figure 1 presents a schematic diagram of the designed MMD2Q, which consists of n 50 Ω resistors connected in parallel, a transformer, 2 Josephson junctions, a Josephson transmission line (JTL), and an SFQ/DC converter (Q2D). Each SNSPD is in series with a 50 Ω on-chip resistor, and the SNSPDs are in parallel with each other, which are connected in series with L 1 .…”

Section: Circuit Designmentioning

confidence: 99%

Photon number resolvability of multi-pixel superconducting nanowire single photon detectors using a single flux quantum circuit

Zhou¹,

Cheng²,

Ren³

et al. 2022

Chinese Phys. B

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Superconducting nanowire single-photon detectors (SNSPDs) are typical switching devices capable of detecting single photons with almost 100% detection efficiency. However, they cannot determine the exact number of incident photons during a detection event. Multi-pixel SNSPDs employing multiple read-out channels can provide photon number resolvability (PNR), but they require increased cooling power and costly multi-channel electronic systems. In this work, a single-flux quantum (SFQ) circuit is employed, and PNR based on multi-pixel SNSPDs is successfully demonstrated. A multi-input magnetically coupled DC/SFQ converter (MMD2Q) circuit with a mutual inductance M is used to combine and record signals from a multi-pixel SNSPD device. The designed circuit is capable of discriminating the amplitude of the combined signals with an accuracy of Φ 0/M. By employing the MMD2Q circuit, the discrimination of up to 40 photons can be simulated. A 4-parallel-input MMD2Q circuit is fabricated, and a PNR of 3 is successfully demonstrated for an SNSPD array with one channel reserved for the functional verification. The results confirm that an MMD2Q circuit is an effective tool for implementing PNR with multi-pixel SNSPDs.

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Design and Verification of SFQ Cell Library for Superconducting LSI Digital Circuits

Cited by 18 publications

References 18 publications

Low power single flux quantum qubit control circuit without high-frequency input

Low power single flux quantum qubit control circuit without high-frequency input

Implementation of an 8-bit bit-slice AES S-box with rapid single flux quantum circuits

Photon number resolvability of multi-pixel superconducting nanowire single photon detectors using a single flux quantum circuit

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