Behavioral Verilog-A Model of Superconductor-Ferromagnetic Transistor

The superconductor-ferromagnetic transistor (SFT) is a novel cryogenic device with the potential to greatly enhance traditional single flux quantum (SFQ) circuits. Since SFT devices are under active development, compact models are necessary to evaluate this device in novel circuits. In this paper, a simplified compact model of a three terminal SFT device is proposed. The model fits the general I-V characteristics of existing devices with 7.4% mean absolute error, while also capturing the transient behavior of the device. The model has been implemented in Verilog-A and simulated in Cadence Spectre. The proposed model enables the simulation of SFQ circuits containing SFT devices, and is reconfigurable to support developments in SFT technology.