Binning is a kind of range partitioning for geometry dependent models like MOSFET's. The purpose is to cover larger geometry ranges (Width and Length) with higher accuracy then the model built-in geometry formulas. Each size range described by the additional model parameters LMIN, LMAX, WMIN and WMAX has its own model parameter set. These model cards are defined by a number extension, like `nch.1'. NGSPICE has a algorithm to choose the right model card by the requested W and L.

This is implemented for BSIM3 (11.2.10) and BSIM4 (11.2.11) models.