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I got this error

Syntax error in .DC command.
expected sweep starting value of source 'sweep'

I have no idea about how the syntax works. I only resorted in asking this site because it was urgent

And here is the code in question:

FILE: p-Enhancement ISFET Model
*********************************************************
*------     ISFET MACROMODEL     -------*
*********************************************************
.PARAM
*-------------------------------------------
*   Constants and common parameters
*-------------------------------------------
* k =   Boltzmann constant          [J/k]
* T =   Actual absolute temperature.        [K]
* q =   Electronic charge           [Coulomb]
* eps0  =   Vacuum dielectric permittivity      [F/m]
* epsw  =   Relative permittivity of the bulk (diffuse layer) solution
* NAv   =   Avogadro constant           [1/mole]
* Lisfx =   Gate length             [m]
* Wisfx =   Gate width              [m]
* Agate =   Gate area               [m**2]
* Cbulk =   Electrolyte concentration       [mole/l]
* Ka    =   Positive dissociation constant      [mole/l]
* Kb    =   Negative dissociation constant      [mole/l]
* Kn    =   Dissociation constant for amine sites   [mole/l]
* Nsil  =   Silanol (or oxide) surface site density [#/m**2]
* Nnit  =   Amine surface site density      [#/m**2]
* Eabs  =   Absolute potential of the standard hydrogen electrode   [V]
* Erel  =   Potential of ref-electrode(Ag/AgCl) relative to H electrode [V]
* Phim  =   Work-function of metal back-contact/electronic charge   [V]
* Philj =   Liquid-junction potential diff. between ref-sol. and electrolyte [V]
* Chieo =   Surface dipole potential        [V]
* Eref  =       (Eabs+Erel-Phim+Chieo+Philj) acts for gate-source ISFET Voltage [V]
*-----------
+   conv=1e3        conv2=1e6
+   k=1.38e-23      eps0=8.85e-12       T=300
+   q=1.602e-19     NAv=6.0221415e23    ET='q/(k*T)'
+   PI='355/113'        PI2='2.0*PI'

+      Nsil=1.0e18  Nnit=9.0e17         ;Si3N4
+      Ka=15.8          Kb=63.1e-9  Kn=1e-10    ;Si3N4
*+     Nsil=8.0e18  Nnit=0.0            *Al2O3
*+     Ka=12.6e-9   Kb=79.9e-9  Kn=0.0      *Al2O3
*+     Nsil=1.0e18  Nnit=0.0            *SiO2
*+     Ka=15.8          Kb=63.1e-9  Kn=0.0      *SiO2
*
+      epsw=78.5    epsihp=32   epsohp=32
+      dihp=0.1n    dohp=0.3n   Cbulk=150m
+      Eabs=4.7     Phim=4.7    Erel=0.205
+      Chieo=3e-3   Philj=1e-3
+      Lisf1=8u     Wisf1=30u   Agate='Wisf1*Lisf1'

+      bb='sqrt(8*eps0*epsw*k*T)'
+      Cb='NAv*Cbulk*conv'
+      KK='Ka*Kb*conv2'
+      Ch='(Agate)*((eps0*epsihp*epsohp)/(epsohp*dihp+epsihp*dohp))'
+      Cd='(Agate)*(bb*ET*0.5)*sqrt(Cb)'
+      Ceq='(1/(1/Cd+1/Ch))'
*
**************************************
***      MOSFET MODEL             ***
**************************************
*  ENHANCEMENT-MODE P-MOSFET
*-------------------------------------
.MODEL MISFET PMOS  LEVEL=2
+   PHI=0.7     TOX=39n     XJ=0.20u    TPG=1
+   VTO=-0.98   DELTA=2.9   LD=58.7n    KP=1.68e-5
+   UO=189      UEXP=0.24   UCRIT=1.15e5    RSH=0.1
+   GAMMA=0.64  NSUB=9.86e15    NFS=1.47e11 NEFF=1.5
+   VMAX=10.0e5 LAMBDA=4.25e-2
+   CGSO=0.185n CGDO=0.185n CGBO=0.43n  CJSW=0.26n
+   CJ=3.40e-4  MJ=0.58     MJSW=0.31   PB=0.90
*
*****************************************************************
.SUBCKT        ISFET      1        6      2     3       4       101
*
Vref    1   10  {Eabs+Erel-Phim+Chieo+Philj}
*
Ceq 10  2   {1/(1/Cd+1/Ch))}
RCeq    10  2   1G
*
EP1 46  0   V = log(KK)+4.606*V(101)
RP1     46  0   1000G
EP2     23  0   V = log(Ka*conv)+2.303*V(101)
RP2     23  0   1000G
*
EPH    2  10  V = (Agate*q/Ceq)*(Nsil*((exp(-2*V(2,10)*ET)-exp(V(46)))/(exp(-2*V(2,10)*ET)+exp(V(23))*exp(-1*V(2,10)*ET)+exp(V(46))))+Nnit*((exp(-1*V(2,10)*ET))/(exp(-1*V(2,10)*ET)+(Kn/Ka)*exp(V(23)))))
RpH   101  0  1K
*************************************************************
MIS   6    2    3    4   MISFET     L='Lisf1'  W='Wisf1'
*
.ENDS         ISFET
****************************************
VpH 500 0          DC      7.3
Vds 450 0          DC     -2.5
Vgs 400 0          DC     -2.0
*
****************************************
*
XIS    400    450    430   0     0    500    ISFET
*
***********************************
.OPTIONS   list node post probe pathnum  itl5=200000  tnom=27 ingold=1
.DC VDS 0 -10 1E-2  SWEEP VGS 0  -2.5  0.5
.PROBE  DC I(Vds)
.OP
.END
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2
  • \$\begingroup\$ Have you tried searching on your favorite internet search tool, or using the help available in LTspice? \$\endgroup\$ – Elliot Alderson Jun 7 '20 at 19:34
  • \$\begingroup\$ @ElliotAlderson yep, google doesn't have any answers for the specific error log. I haven't used the available help in LTSpice, I might try it. \$\endgroup\$ – TTbulaski Jun 8 '20 at 3:37
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There are some helpful suggestions here. Some of them apply in your case.

  1. Remove all blank lines.
  2. Remove the SWEEP word from the .DC card.
  3. Fix the extra ')' on the CEQ card.
  4. LTspice .OPTIONS doesn't support the following, so remove them:

    itl5

    pathnum

    probe

    node

    ingold

    post

  5. Convert all "E" cards to "B" cards.

That should get you into running mode, anyway.

However, I'd recommend removing everything from the .OPTIONS and below, when pasting it into LTspice. This sets up your models and subcircuits and circuit, without actually specifying which run you want to perform.

Then separately, set up the .OPTIONS card in a spice "text" card that you add, separately on the schematic. Similarly, place the .DC card into its own spice "text" card. And then similarly again, place the .PROBE and .OP cards into yet another spice "text" card, but in this case I'd recommend telling LTspice that this pair of cards are just "comments" for now. You can then run the .DC simulation and display plots, if you want. Afterwards, just comment out the .DC card and uncomment the .PROBE and .OP cards and run it again.

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