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-- package under the terms of the "GNU GENERAL PUBLIC LICENSE" version 2,
-- June 1991. A copy of this license agreement can be found in the file
-- "COPYING", distributed with this archive.
-- You should have received a copy of the GNU General Public License
-- along with VESTs; if not, write to the Free Software Foundation,
-- Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
-- ---------------------------------------------------------------------
--
-- $Id: test145.ams,v 1.1 2002-03-27 22:11:18 paw Exp $
-- $Revision: 1.1 $
--
-- ---------------------------------------------------------------------
----------------------------------------------------------------------
-- SIERRA REGRESSION TESTING MODEL
-- Develooped at:
-- Distriburted Processing Laboratory
-- University of cincinnati
-- Cincinnati
----------------------------------------------------------------------
-- File : test145.ams
-- Author(s) : Geeta Balarkishnan(gbalakri@ececs.uc.edu)
-- Created : June 2001
----------------------------------------------------------------------
-- Description :
-- this is a mos model. It tests for the correctness of the procedural
-- statement.
--
-- the model accepts the mos data as generic constants. The terminals
-- are defined as of nature electrical.
-- it also tests the alias declaration for real'low.
-- Charges associated with the 4 terminals are declared as quantities.
-- The voltage associated with each of them is also defined.
-- a signal is used to drive i.e to carry out a generic initialization.
-- The various mos equations are evaluated depending on the conditions.
-- The equations for charges and currents are evaluated.
----------------------------------------------------------------------
package mosdata is
NATURE electrical is real across real through;
FUNCTION SIN(X : real) RETURN real;
FUNCTION EXP(X : real) RETURN real;
FUNCTION SQRT(X : real) RETURN real;
FUNCTION POW(X,Y : real) RETURN real;
alias undefined is real'low;
constant Temperature: real:=27.0;
constant eps0 : real :=8.85418e-12;
constant Ni : real :=1.45e16;
constant Boltzmann : real :=1.380662e-23;
constant echarge: real :=1.6021892e-19;
constant epsSiO2 : real :=3.9*eps0;
constant epsSi : real :=11.7*eps0;
constant kTQ : real :=Boltzmann*temperature/echarge;
constant pi: real := 3.14159;
end package mosdata;
use work.mosdata.all;
entity mos is
generic(
width : real:=1.0E-4;
length : real:=1.0E-4;
channel: real :=1.0;
kp :real:= 2.0E-5;
gamma :undefined;
phi :undefined;
tox :real:= 1.0E-7;
nsub :real:= 0.0;
nss :real:=0.0;
nfs :real:= 0.0;
tpg :real:= 1.0;
xj :real:=0.0;
ld :real:= 0.0;
u0 :real:= 600.0;
vmax :real:=0.0;
xqc :real:= 1.0;
kf :real:=0.0;
af :real:=1.0;
fc :real:=0.5;
delta :real:=0.0;
theta :real:=0.0;
eta :real:=0.0;
Sigma :real:=0.0;
kappa :real:=0.2 );
port ( terminal drain, gate, source, bulk : electrical);
end entity mos;
architecture amos of mos is
quantity Qc, Qb, Qg: real;
quantity Qcq, Qbq, Qgq : real; -- channel, bulk and gate charges
quantity Vdsq across drain to source;
quantity Vgsq across gate to source;
quantity Vbsq across bulk to source;
quantity Idq through drain;
quantity Igq through gate;
quantity Isq through source;
quantity Ibq through bulk;
signal Initialized: boolean; -- use a signal as generic initialisation
begin
MOSeqns: procedural is
variable
cox,vt,beta,sigma,nsub,Phi,Gamma,nss,ngate,A,B,C,D,Vfb,fshort,
wp,wc,sqwpxj,vbulk,delv,vth,Vgstos, Vgst,
Ueff,Tau,Vsat,Vpp,fdrain,
stfct,leff,xd,qnfscox,fn,dcrit,deltal,It,Ids,R,Vds,Vgs,Vbs,
forward ,egfet,fermig, mobdeg: real;
begin -- procedural statements
if not Initialized then
if tox<=0.0 then
cox:=epsSiO2/1.0e-7;
else
cox:=epsSiO2/tox;
end if;
if kp = 0.0 then
beta:=cox*u0;
else
beta:=kp;
end if;
nsub := nsub * 1.0e6; -- scale nsub to SI units
if (phi = undefined) then
if (nsub > 0.0) then
if (0.1<2.0*KTQ*(nsub/Ni)) then
Phi:=(2.0*kTQ*(nsub/Ni));
else
Phi:=0.1;
end if;
else
Phi:=0.6;
end if;
else
Phi:=phi;
end if;
if (gamma = undefined) then
if (nsub > 0.0) then
Gamma:=sqrt(2.0*epsSi*echarge*nsub)/cox;
else
Gamma:=0.0;
end if;
else
Gamma:=gamma;
end if;
nss:=nss*1.0e4; -- Scale to SI
ngate:=gamma*1.0e4; -- Scale to SI
leff:=length-2.0*ld;
if leff>0.0 then
Sigma:= eta * 8.15e-22/(cox*leff*leff*leff);
else
Sigma:=0.0;
end if;
if nsub>0.0 then -- N.B. nsub was scaled, above.
xd:=sqrt(2.0*epsSi/(echarge*nsub));
else
xd:=0.0;
end if;
if (nfs>0.0) and(cox>0.0) then
qnfscox:=echarge*nfs/cox;
else
qnfscox:=0.0;
end if;
if cox>0.0 then
fn:=delta*pi*epsSi*0.5/(cox*width);
else
fn:=delta*pi*epsSi*0.5*tox/epsSiO2;
end if;
--Scale beta and convert cox from Fm^-2 to F
beta:=beta*width/leff;
cox:=cox*width*leff;
Initialized <= true;
end if; -- not initialized
Vds:=channel*Vdsq;
if Vds>=0.0 then
Vgs:=channel* Vgsq;
Vbs:=channel* Vbsq;
forward:=1.0;
else
Vds:=-Vds;
Vgs:=channel* Vgsq;
Vbs:=channel* Vbsq;
forward:=-1.0;
end if;
if Vbs<=0.0 then
A:=Phi-Vbs;
D:=sqrt(A);
else
D:=2.0*sqrt(Phi)*Phi/(2.0*Phi+Vbs);
A:=D*D;
end if;
Vfb:=Vt-Gamma*sqrt(Phi)-Sigma*Vds;
if (xd=0.0) OR (xj=0.0) then
fshort:=1.0;
else
wp:=xd*D;
wc:=0.0631353*xj+0.8013292*wp-0.01110777*wp*wp/xj;
sqwpxj:=sqrt(1.0-(wp*wp/((wp+xj)*(wp+xj))));
fshort:=1.0-((ld+wc)*sqwpxj-ld)/leff;
end if;
vbulk:=Gamma*fshort*D+fn*A;
if nfs=0.0 then
delv:=0.0;
else
delv:=kTQ*(1.0+qnfscox+vbulk*0.5/A);
end if;
vth:=Vfb+vbulk;
Vgstos:=Vgs-Vfb;
if (vgs-vth > delv) then
Vgst:=Vgs-vth;
else
Vgst:= delv;
end if;
if (vgs>=vth) or (delv/=0.0) then
if (Vbs<=0.0) or (Phi /= 0.0) then
B:=0.5*Gamma/D+fn;
else
B:=fn;
end if;
mobdeg:=1.0/(1.0+theta*Vgst);
if (vmax /=0.0) then
Ueff:=u0*mobdeg;
Tau:=Ueff/Leff*vmax;
else
Tau:=0.0;
end if;
Vsat:=Vgst/(1.0+B);
Vsat:=Vsat*(1.0-0.5*Tau*Vsat); -- not quite the same as SPICE
if (vds<Vsat) then
Vpp:=vds;
else
Vpp:= Vsat;
end if;
fdrain:=1.0/(1.0+Tau*Vpp);
if (Vgs<vth+delv) and (nfs>0.0) then
stfct:=exp((Vgs-vth-delv)/delv);
else
stfct:=1.0;
end if;
if Vds>=Vsat then
if (kappa>0.0) and (xd>0.0) then
if vmax=0.0 then
deltal:=sqrt(kappa*xd*xd*(Vds-Vsat));
else
dcrit:=(xd*xd*vmax*0.5)/(Ueff*(1.0-fdrain));
deltal:=sqrt(kappa*xd*xd*(Vds-Vsat)+dcrit*dcrit)-dcrit;
end if;
if deltal<=0.5*Leff then
C:=Leff/(Leff-deltal);
else
C:=4.0*deltal/Leff;
end if;
else
C:=1.0;
end if;
else
C:=1.0;
end if;
It:=Vgst-Vpp*(1.0+B)*0.5;
Beta:=Beta*mobdeg;
Ids:=Beta*Vpp*It*C*fdrain*stfct;
else
-- Cutoff
Ids:=0.0;
end if; -- vgs >= vth
if Cox /= 0.0 then
--Charges
if Vgs<=vth then
if Gamma /= 0.0 then
if Vgstos < -A then
Qg:=Cox*(Vgstos+A); -- Accumulation
else
Qg:=0.5*Gamma*Cox*(sqrt(4.0*(Vgstos+A)+Gamma*Gamma-Gamma));
end if ; -- vgstos <-A
else-- Gamma = 0.0
Qg:=0.0;
end if; -- gamma /= 0
Qb:=-Qg;
Qc:=0.0;
else
-- depletion mode:
R:=(1.0+B)*Vpp*Vpp/(12.0*It);
Qg:=Cox*(Vgstos-Vpp*0.5+R);
Qc:=-Cox*(Vgst+(1.0+B)*(R-Vpp*0.5));
Qb:=-(Qc+Qg);
end if;
else
Qg:=0.0;
Qc:=0.0;
Qb:=0.0;
end if; -- cox /= 0
-- equations for charges (in a procedural we have assignments to
--quantitites):
Qcq := Qc;
Qgq := Qg;
Qbq := Qb;
-- equations for currents:
Idq := channel*forward*Ids+channel*xqc*Qc'dot;
Igq := channel*Qg'dot;
Ibq := channel*Qb'dot;
Isq := -Idq - Igq - Ibq;
end procedural;
end architecture amos;