A circuit simulation model for Schottky-barrier diodes is presented which accurately reproduces the diode's forward I-V characteristics. This is achieved by the inclusion of the nonlinear (current-dependent) series resistance typically observed in planar Schottky-barrier diodes. The diode model is targeted for large-signal transient and dc bias analysis where precise solutions are required. Noteworthy features of the model are (a) an easily determined parameter set from either direct measurements or geometrical and process data, (b) requires only one additional node over the constant-resistance diode models, and (c) is applicable to a wide variety of diode geometries. Finally, an example is given to demonstrate the accuracy of the diode model.