Schaltungstechnik

6.2 Arbeitspunkteinstellung und Arbeitspunktstabilität 377
-- cut off region
ids == 1.0e-9 * vds;
elsif ((vds = vth)) use
-- linear region
ids == vds*beta*((vgs - vth) - (vds/2.0))*(1.0 + lambda*vds);
else
-- saturation region (vds > (vgs-vth)) AND (vgs >= vth)
ids == (beta/2.0)*(((vgs - vth)**2.0))*(1.0 + lambda*vds);
end use;
-- capacitances gate to bulk, gate to drain, gate to source
if (vgs vth and vds < vsat use
cgb == 0.0 + cgbo;
cgd==(2.0/3.0)*cox*(1.0-((vsat-vbs)/(2.0*(vsat-vbs)-vbd))**2.0)+cgdo;
cgs==(2.0/3.0)*cox*(1.0-((vsat-vds)/(2.0*(vsat-vbs)-vbd))**2.0)+cgso;
else
cgb == 0.0 + cgbo;
cgd == 0.0 + cgdo;
cgs == (2.0/3.0)*cox + cgso;
end use;
-- capacitance bulk to source
if(vbs