This paper describes an explicit analytical charge-based model of an undoped independent double gate (DG) MOSFET. This model is based on Poisson equation resolution and field continuity equations. Without any fitting parameter or charge sheet approximation, it provides explicit analytical expressions of both inversion charge and drain current considering long undoped transistor. Consequently, this is a fully analytical and predictive model allowing describing planar DG MOSFET as well as FinFET structures. The validity of this model is demonstrated by comparison with Atlas simulations. (c) 2006 Elsevier Ltd. All rights reserved.