Piezoelectric materials are widely used for many applications such as sensors, actuators. Today, their integration in microelectronics processes like CMOS requires the development of advanced realistic behavioral models. Until now, these models were limited to only one ceramic's operation mode, i.e., thickness or planar. Moreover, the robustness of piezo-electronic system cannot be adequately addressed as long as models are not improved, in particular by taking into account further real phenomena. This article proposes to merge, in a new behavioral model, the two operation modes. It is demonstrated that the electrical behavior of the proposed model is in very good agreement with the real ceramic behavior.