Robert S. Aviles

2papers

2 Papers

95.4ETApr 9
qPRO-AQFP: Post-Routing Optimization of AQFP Circuits with Delay Line Clocking

Robert S. Aviles, Ziyu Liu, Jingkai Hong et al.

Adiabatic Quantum-Flux-Parametron (AQFP) logic is an ultra-low-power superconducting logic family with energy consumption approaching the Shannon limit, making it attractive for quantum computing control and cryogenic computing systems. Traditional AQFP designs face significant physical design challenges due to strict gate-level clocking requirements and limited interconnect lengths, leading to substantial buffer overhead and difficult timing closure. Recently, delay-line clocking of AQFP has been proposed to improve timing margins and reduce latency by enabling more flexible clock scheduling. However, prior work has primarily focused on placement and latency minimization, while relying on fixed timing parameters that do not capture the frequency dependence of AQFP setup and hold constraints. To address this limitation, we propose a frequency-aware post-routing optimization framework that jointly optimizes clock period, latency, and timing slack under user-specified weighting. Experimental results across common benchmarks achieve 100% post-routing timing closure across a range of performance--latency--slack trade-offs. Our approach also automates phase-skipping, reducing path-balancing buffer insertion by 34% on average while only reducing operating frequency by 4%.

84.6ETMar 26
Generalizable Verilog Modeling Framework for Synchronous and Asynchronous Superconducting Pulse-Based Logic Gates

Elisabeth Feng, Robert S. Aviles, Peter A. Beerel

Superconducting Single Flux Quantum (SFQ) logic offers a promising platform for ultra-low-power, high-frequency computing. However, their pulse-based nature poses challenges for scalable modeling, design, and verification using conventional hardware description languages (HDLs), which are designed for level-based digital logic. Prior efforts have required complex Verilog support modules to enable Standard Delay Format (SDF) compatibility and have provided limited coverage of SFQ cell types. This work presents a Verilog-based modeling framework for SFQ gates that enables functional and timing verification while maintaining compatibility with Standard Delay Format (SDF) back annotation and is the first framework to support both synchronous and asynchronous SFQ gates. The proposed models are validated through device-level simulations, demonstrating correct functionality and timing constraint coverage. RTL simulation of mixed synchronous-asynchronous circuits further demonstrate the utility of the proposed framework.