Fault injection techniques have been proposed for years to early analyze the dependability characteristics of digital circuits. Very few attempts have however been reported to perform the same task in analog parts. Furthermore, these attempts are all based on parametric variations. With the increasing number of mixed signal circuits, a unified approach becomes mandatory to globally validate the digital and analog parts, while taking into account real faults occurring in the field, e.g. SEUs. In this paper, a global analysis flow is proposed, based on a high-level model of the circuit. The possibility to inject transient faults in the different parts is discussed. The results obtained on a case study are reported to show the feasibility of the injection in analog blocks.