Global convergence analysis of mixed-signal systems

This paper proposes two practical approaches to address global convergence failures, commonly encountered in mixed-signal systems in which analog and digital components closely interact. That is, a nominally-working system may fail intermittently depending on its initial conditions upon start-up. The first approach uses a data clustering analysis and verifies global convergence with randomly-selected pilot simulations. The second approach adopts the practice of representing indeterminate states with X by defining its equivalent concept for analog based on entropy. With oscillator and phase-locked loop examples, it is demonstrated that the proposed approaches can effectively detect the failures and guide designers where to add more resets to prevent them.