// Varactor Model // // Version 1b, 23 October 2006 // // Ken Kundert // // downloaded from the designer's guide (www.designers-guide.org). // post any questions on www.designers-guide.org/forum. // Documentation on the model can be found at www.designers-guide.org/Modeling `include "disciplines.vams" module varactor(p, n); inout p, n; electrical p, n; parameter real c0 = 1p from (0:inf); // nominal capacitance (F) parameter real c1 = 0.5p from [0:c0); // maximum capacitance change from nominal (F) parameter real v0 = 0; // voltage for nominal capacitance (V) parameter real v1 = 1 from (0:inf); // voltage change for maximum capacitance (V) real q, v; analog begin v = V(p,n); q = c0*v + c1*v1*ln(cosh((v - v0)/v1)); I(p, n) <+ ddt(q); end endmodule