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May 20, 2015
09:50 AM
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May 20, 2015
09:50 AM
The top-level model for this MOSFET calls another subcircuit: S3_250_n_var.
The S3_250_n_var subcircuit contains this line: .PARAM bm={c/((1/gmin-Rs)**2*Inn*a*(T0/Tref)**nmu3)}
This subcircuit won't simulate because the model sets both gmin and Rs to 1, which causes the expression to evaluate to "INF":
.SUBCKT S3_250_n_var dd g s0 Tj PARAMS: a=1 dVth=0 dR=0 dgfs=0 Inn=1 Unn=1 Rmax=1 gmin=1 Rs=1 Rp=1 dC=0 Rm=1u heat=0
Has someone successfully used this model? What should be the values for gmin and Rs?
The S3_250_n_var subcircuit contains this line: .PARAM bm={c/((1/gmin-Rs)**2*Inn*a*(T0/Tref)**nmu3)}
This subcircuit won't simulate because the model sets both gmin and Rs to 1, which causes the expression to evaluate to "INF":
.SUBCKT S3_250_n_var dd g s0 Tj PARAMS: a=1 dVth=0 dR=0 dgfs=0 Inn=1 Unn=1 Rmax=1 gmin=1 Rs=1 Rp=1 dC=0 Rm=1u heat=0
Has someone successfully used this model? What should be the values for gmin and Rs?
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ispn:4255:1:0
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l1:144:1:0
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l2:152:1:0
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l3:1341:1:0
2 Replies
May 20, 2015
11:20 PM
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May 20, 2015
11:20 PM
Parameter RS and gmin are set as .PARAM Rs=564u and gmin=3 in .SUBCKT BSZ42DN25NS3
.SUBCKT BSZ42DN25NS3 drain gate source Tj Tcase PARAMS: dVth=0 dRdson=0 dgfs=0 dC=0 Zthtype=0 Ls=1n Ld=1n Lg=3n
.PARAM Rs=564u Rg=2 Rd=50u Rm=250u
.PARAM Inn=2.5 Unn=10 Rmax=427m gmin=3
.PARAM RRf=497m Rrbond=11m Rtb=5 g2=947m
.PARAM act=1.274
.FUNC Pb(I,dT,Rb) {Rb/(2*Rtb)*(I-limit(dT/(max(I,1n)*Rb)+RRf*I*g2,0,I))**2}
X1 d1 g s Tj S3_250_n_var PARAMS: a={act} dVth={dVth} dR={dRdson} dgfs={dgfs} Inn={Inn} Unn={Unn}
+Rmax={Rmax} gmin={gmin} Rs={Rs} Rp={Rd} dC={dC} Rm={Rm}
The simulation works fine.
.SUBCKT BSZ42DN25NS3 drain gate source Tj Tcase PARAMS: dVth=0 dRdson=0 dgfs=0 dC=0 Zthtype=0 Ls=1n Ld=1n Lg=3n
.PARAM Rs=564u Rg=2 Rd=50u Rm=250u
.PARAM Inn=2.5 Unn=10 Rmax=427m gmin=3
.PARAM RRf=497m Rrbond=11m Rtb=5 g2=947m
.PARAM act=1.274
.FUNC Pb(I,dT,Rb) {Rb/(2*Rtb)*(I-limit(dT/(max(I,1n)*Rb)+RRf*I*g2,0,I))**2}
X1 d1 g s Tj S3_250_n_var PARAMS: a={act} dVth={dVth} dR={dRdson} dgfs={dgfs} Inn={Inn} Unn={Unn}
+Rmax={Rmax} gmin={gmin} Rs={Rs} Rp={Rd} dC={dC} Rm={Rm}
The simulation works fine.
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May 21, 2015
05:41 AM
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May 21, 2015
05:41 AM
My version of SPICE simulator must not be passing the top-level values down to the lower-level subcircuit. Changing the values in the lower-level subcircuit allows the simulation to run properly.
Thanks.
Thanks.