Author Topic: Ltspice ? about warnings in a log file.  (Read 492 times)

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Offline rolloman

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Ltspice ? about warnings in a log file.
« on: July 07, 2017, 10:46:32 PM »
My simulation runs fine but I get this text shown below that pops up after each run ends. It started when I added the part that I have included below also using the .include. Is this something I need to resolve, or can it be ignored. I am kinda new at Ltspice so don't know what to expect sometimes with what it does. Thanks to anyone that can help.
Circuit: * C:\Users\owner\Documents\LTspiceXVII\Custom Amp.asc

Error on line 1747 : .model m6:bsim3 nmos (level=7 version=3.1 mobmod=3 capmod=2 paramchk=1 nqsmod=0  tox=970e-10 xj=1.4e-6 nch=1.7e17 ua=1.6e-9  u0=700 vsat=1.0e5 drout=3.0 pvag=5  delta=0.10 pscbe2=0 rsh=1.0e-3 pdiblc2=1e-7  vth0=3.50 voff=-0.1 nfactor=1.1  lint=5.90e-7 dlc=5.90e-7 fc=0.5  cgso=1.12e-9 cgsl=0 cgdo=1.05e-14  cgdl=1.68e-9 cj=0 cf=0  ckappa=0.20 kt1=-2.07 kt2=0  ua1=1.02e-9 nj=10 )
   * Unrecognized parameter "fc" -- ignored
Error on line 1747 : .model m5:bsim3 nmos (level=7 version=3.1 mobmod=3 capmod=2 paramchk=1 nqsmod=0  tox=970e-10 xj=1.4e-6 nch=1.7e17 ua=1.6e-9  u0=700 vsat=1.0e5 drout=3.0 pvag=5  delta=0.10 pscbe2=0 rsh=1.0e-3 pdiblc2=1e-7  vth0=3.50 voff=-0.1 nfactor=1.1  lint=5.90e-7 dlc=5.90e-7 fc=0.5  cgso=1.12e-9 cgsl=0 cgdo=1.05e-14  cgdl=1.68e-9 cj=0 cf=0  ckappa=0.20 kt1=-2.07 kt2=0  ua1=1.02e-9 nj=10 )
   * Unrecognized parameter "fc" -- ignored
Warning: Pscbe2 = 0 is not positive.
Warning: Pd = 0 is less than W.
Warning: Ps = 0 is less than W.
Warning: Pscbe2 = 0 is not positive.
Warning: Pd = 0 is less than W.
Warning: Ps = 0 is less than W.
Instance "m:m3:1": Length shorter than recommended for a level 1 MOSFET.
Instance "m:m3:1": Width narrower than recommended for a level 1 MOSFET.
Per .tran options, skipping operating point for transient analysis.
Heightened Def Con from 0.589734 to 0.589734

Date: Fri Jul 07 08:38:35 2017
Total elapsed time: 36.055 seconds.

tnom = 27
temp = 27
method = modified trap
totiter = 236482
traniter = 236482
tranpoints = 62603
accept = 46734
rejected = 15870
matrix size = 262
fillins = 428
solver = Normal
Matrix Compiler1: 44.92 KB object code size  23.9/41.1/[8.5]
Matrix Compiler2: 29.26 KB object code size  7.3/18.3/[4.6]

Heres the part file that caused this error log when I added it with a .include statement.
**************** Power Discrete MOSFET Electrical Circuit Model *****************
** Product Name: FQH8N100C
** 1000V N-Channel MOSFET and TO-247
** Model Type: BSIM3V3
**-------------------------------------------------------------------------------
.SUBCKT FQH8N100C 2 1 3   
*Nom Temp=25 deg C
Dbody 7 5    DbodyMOD
Dbreak 5 11  DbreakMOD
Ebreak 11 7 17 7 1000
Lgate 1 9    1.125e-9
Ldrain 2 5   1.440e-9
Lsource 3 7  9.106e-10
RLgate 1 9   11.25
RLdrain 2 5  14.4
RLsource 3 7 9.11
Rgate 9 6    0.5
It 7 17      1
Rbreak 17 7  RbreakMOD 1
.MODEL RbreakMOD RES (TC1=1.18e-3 TC2=-1.15e-6)
.MODEL DbodyMOD D (IS=6.45e-9  N=1.5      RS=4.44e-3   TRS1=3.8e-3 TRS2=5.8e-6
+ CJO=1.76e-09     M=0.53      VJ=0.45    TT=1.09e-6   XTI=3       EG=1.154)
.MODEL DbreakMOD D (RS=100e-3 TRS1=1.0e-3 TRS2=5.0e-6)
Rdrain 5 16 RdrainMOD 1.2
.MODEL RdrainMOD RES (TC1=8.8e-3 TC2=1.66e-5)
M_BSIM3 16 6 7 7 Bsim3 W=1.08 L=2.0e-6 NRS=1
.MODEL  Bsim3 NMOS (LEVEL=7 VERSION=3.1 MOBMOD=3 CAPMOD=2 PARAMCHK=1 NQSMOD=0
+ TOX=970e-10    XJ=1.4e-6      NCH=1.7e17      UA=1.6e-9
+ U0=700         VSAT=1.0e5     DROUT=3.0       PVAG=5
+ DELTA=0.10     PSCBE2=0       RSH=1.0e-3      PDIBLC2=1e-7
+ VTH0=3.50      VOFF=-0.1      NFACTOR=1.1     
+ LINT=5.90e-7   DLC=5.90e-7    FC=0.5
+ CGSO=1.12e-9   CGSL=0         CGDO=1.05e-14
+ CGDL=1.68e-9   CJ=0           CF=0
+ CKAPPA=0.20    KT1=-2.07      KT2=0
+ UA1=1.02e-9    NJ=10 )
.ENDS

******************** Power Discrete MOSFET Thermal Model ************************
** 1000V N-Channel MOSFET and TO-247
**-------------------------------------------------------------------------------
.SUBCKT FQH8N100C_Thermal TH TL
CTHERM1 TH 6 1.12e-5
CTHERM2 6 5  1.53e-3
CTHERM3 5 4  1.82e-2
CTHERM4 4 3  6.45e-2
CTHERM5 3 2  8.12e-2
CTHERM6 2 TL 5.21e-1
RTHERM1 TH 6 4.00e-4
RTHERM2 6 5  8.10e-3
RTHERM3 5 4  3.40e-2
RTHERM4 4 3  9.10e-2
RTHERM5 3 2  1.02e-1
RTHERM6 2 TL 3.24e-1
.ENDS FQH8N100C_Thermal
**-------------------------------------------------------------------------------
** Creation: Jan.-05-2010   Rev.: 0.0
** Fairchild Semiconductor

 

Offline UselessUser

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Re: Ltspice ? about warnings in a log file.
« Reply #1 on: December 07, 2017, 12:46:13 AM »
I got the same for Pscbe2, Pd, Ps, and Fc when using the Fairchild model for a BSS138W mosfet in LTSpice.  I just want to use the mosfet for basic switching and don't have time to become an expert in modelling each one I use.  It seems to run just fine, but over what region would results be valid?

OnSemi Tech support gave me this.

This model was made by Fairchild before the merger. In general:
FC is the depletion capacitance coefficient and will probably have little effect on the model as long as it is within the normal range of .1 to .8 (typical is .5)


From https://www.seas.upenn.edu/~jan/spice/PSpice_ReferenceguideOrCAD.pdf

PD and PS
The drain and source diffusion perimeters. Their default value is 0.

PSCBE2 second substrate current body effect coefficient m/V 1.0E-5


But none of this helps me to know the region in which the model is valid.
 


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