PSP-Based Scalable MOS Varactor Model

A physically based scalable model for MOS Varactors is presented. The model includes a PSP-based analytical surface potential charge formulation, MOS varactor specific gate current models, and physical geometry and process parameter based parasitic modeling. Key device performances of capacitance and quality factor Q are validated over voltage, frequency, and geometry, for several technologies. The model, implemented in Verilog-A, provides robust and accurate RF simulation of MOS varactors. A VCO design application is detailed.