A Compact IGFET Charge Model

A new IGFET charge model, consistent with the recently published Compact Short-Channel IGFET Model [1], [2], is presented. It is simple, accurate, and suitable for circuit simulation applications. Charge conservation is guaranteed by using charge as the state variable. The partitioning of channel charge into drain and source components is given significant attention. This partitioning changes smoothly from 40/60 in the saturation region asymptotically to 50/50 in the triode region. The terminal charges are well behaved over all regions of operation. This charge model and its dc characteristic counterpart, derived from the same considrerations of MOS device physics, form a unified model previously unavailable.