This paper presents a new model for the current factor mismatch of the MOS transistor. It demonstrates that the impact of interface states is negligible. Therefore, the analytical model is based on the random variations of the dopant number in the channel region, similarly to V, mismatch model. As a result, the theoretical value of the matching parameter A(beta) is 0.26% mum for NMOS and 0.51% mum for PMOS transistors that is close to experimental results. (C) 2003 Elsevier Science Ltd. All rights reserved.