In this paper, we propose an analytical model for read stability metric (read margin) of sub-45nm SRAM cells. First, analytical expressions for Vread and Vtrip of the cell are derived. The expressions are obtained using a simple model for the I-V characteristics of the transistors valid for sub-45nm technologies. The I-V model, which is based on the n-th power model, has integer powers of voltage. The accuracy of the analytical model is verified by comparing its results with those of HSPICE simulations. The results show a very good accuracy for the proposed model for a wide range of transistor sizes. The accuracy of the models is also verified in the presence of threshold voltage fluctuations.