This paper presents the characterization and modeling process of MASMOS structures by means of a classical compact three-port electrical non-linear model approach. From DC and S-parameters measurements, a large signal model (LSM) has been developed for two different MASMOS structures. The proposed LSM and associated modeling approach have been validated through load pull measurements with different harmonic load conditions. Then, generic multi-tone measurements have been carried out making use of an innovative test bench to quantify linearity performances of MASMOS structures. The model is used in a power amplifiers design flow for LTE applications and is expected to allow a significant reduction of simulation time, compared with technological-oriented model as BSIM3.