Computational routine
eng
NMOS
class NMOS "Simple MOS Transistor"
parameter Real W=20.e-6 "Width";
parameter Real L=6.e-6 "Length";
parameter Real Beta=0.041e-3 "Transconductance parameter";
parameter Real Vt=0.8 "Zero bias threshold voltage";
parameter Real K2=1.144 "Bulk threshold parameter";
parameter Real K5= 0.7311"Reduction of pinch-off region";
parameter Real dW=-2.5e-6 "narrowing of channel";
parameter Real dL= -1.5e-6"shortening of channel";
parameter Real RDS=1.e+7 "Drain-Source-Resistance";
Pin D "Drain";
Pin G "Gate";
Pin S "Source";
Pin B "Bulk";
Real v;
Real uds;
Real ubs;
Real ugst;
Real ud;
Real us;
Real id,gds;
equation
//assert (L + dL > 0, "Effective length must be positive");
//assert (W + dW > 0, "Effective width must be positive");
gds = if noEvent(RDS < 1.e-20 and RDS > -1.e-20) then 1.e20 else 1/RDS;
v = Beta*(W + dW)/(L + dL);
ud = if noEvent(D.v < S.v) then S.v else D.v;
us = if noEvent(D.v < S.v) then D.v else S.v;
uds = ud - us;
ubs = if noEvent(B.v > us) then 0 else B.v - us;
ugst = (G.v - us - Vt + K2*ubs)*K5;
id = if noEvent(ugst <= 0) then uds*gds else if noEvent(ugst > uds) then v*uds*(ugst
- uds/2) + uds*gds else v*ugst*ugst/2 + uds*gds;
G.i = 0;
D.i = if noEvent(D.v < S.v) then -id else id;
S.i = -D.i;
B.i = 0;
end NMOS;