A new optimization procedure for single flux quantum circuits

We have proposed a new optimization procedure for single flux quantum circu its. We have combined Monte-Carlo method with the critical margin method. F irst, Monte-Carlo method is used to scatter circuit parameters around the i nitial values. Typically, 50 sets of the circuit parameters are created. Th en, the critical margin method is applied in each set. Finally, a circuit t hat has the largest critical margin among these sets is chosen as an optimi zed circuit. We fabricated circuits with parameter sets before and after ea ch step optimization circuits and demonstrated that the circuit after the t hird step optimization was operated with large bias margins at the designed value. (C) 2001 Elsevier Science B.V. All rights reserved.