Oscillatory metastability in homogeneous and inhomogeneous flip-flops

Abstract

Models which describe oscillatory metastability for several types of flip-flops are proposed. A constant-slew-rate model is first used to find the bounds on circuit parameters which discriminate between analog and oscillatory metastability. A variable-slew-rate model is then used to evaluate resolving time as a function of input timing. Two classes of flip-flops, homogeneous and inhomogeneous, are defined, and their performances in terms of resolving time are compared. It is shown that, in many cases, inhomogeneous flip-flops provide significant improvements with respect to resolving time when oscillatory metastability is involved. The analytical results are verified by comparison with SPICE simulation result