MOS in NgSpice

[Fahim]

Hi,

I am trying to write simple netlist which uses pmos. I am not getting any error but when I plot i(V3) vs v(vin) i got some weired waveform. Basically I am trying to plot id vs vgs.

Am I using pmos correctly. My code are as follow.

**PMOS Example
V1 vdd 0 5V
V2 vss 0 0v
V3 in vss pulse(0 3 0 100p 100p 1.9n 4n)
R1 in vin 10k
R2 out 0 4k
Mp1 out vin vdd vdd pch l=0.35u w=20.0u
.MODEL pch PMOS
.tran .1n 200n
.End

[Fahim]

Hi,
Actually I am writing script for which will keeps changing the value of vth and to plot id vs vgs.

I have modefied it.

But I dont know how to use plot in control statement.

V1 vdd 0 5V
V2 vss 0 0v
V3 in vss pulse(0 3 0 100p 100p 1.9n 4n)
R1 in vin 10k
R2 out 0 4k
Mp1 out vin vdd vdd pch l=0.35u w=20.0u
.MODEL pch PMOS
+Level = 49
+Lint = 3.e-08      Tox = 4.2e-09 
+Vth0 = -0.4        Rdsw = 450 
+lmin=1.8e-7        lmax=1.8e-7     
+wmin=1.8e-7        wmax=1.0e-4     
+version =3.1       Xj= 7.0000000E-08         
+Nch= 5.9200000E+17     lln= 1.0000000            
+lwn= 1.0000000         wln= 0.00
+wwn= 0.00              ll= 0.00
+lw= 0.00               lwl= 0.00                   
+wint= 0.00     wl= 0.00                  
+ww= 0.00               wwl= 0.00
+Mobmod=1               binunit= 2                                    
+Dwg= 0.00              Dwb= 0.00 
+hdif=0.00      rsh= 0 
+K1= 0.5560000          K2= 0.00 
+K3= 0.00               Dvt0= 11.2000000            
+Dvt1= 0.7200000    Dvt2= -1.0000000E-02      
+Dvt0w= 0.00            Dvt1w= 0.00 
+Dvt2w= 0.00            Nlx= 9.5000000E-08          
+W0= 0.00       K3b= 0.00                 
+Ngate= 5.0000000E+20 
+Vsat= 1.0500000E+05    Ua= -1.2000000E-10          
+Ub= 1.0000000E-18 
+Uc= -2.9999999E-11     Prwb= 0.00 
+Prwg= 0.00             Wr= 1.0000000               
+U0= 8.0000000E-03  A0= 2.1199999             
+Keta= 2.9999999E-02    A1= 0.00 
+A2= 0.4000000          Ags= -0.1000000             
+B0= 0.00       B1= 0.00 
+Voff= -6.40000000E-02      NFactor= 1.4000000          
+Cit= 0.00      Cdsc= 0.00                
+Cdscb= 0.00            Cdscd= 0.00 
+Eta0= 8.5000000        Etab= 0.00                  
+Dsub= 2.8000000    Pclm= 2.0000000           
+Pdiblc1= 0.1200000     Pdiblc2= 8.0000000E-05 
+Pdiblcb= 0.1450000     Drout= 5.0000000E-02        
+Pscbe1= 1.0000000E-20 
+Pscbe2= 1.0000000E-20     Pvag= -6.0000000E-02        
+Delta= 1.0000000E-02 
+Alpha0= 0.00              Beta0= 30.0000000 
+kt1= -0.3700000           kt2= -4.0000000E-02         
+At= 5.5000000E+04     Ute= -1.4800000           
+Ua1= 9.5829000E-10        Ub1= -3.3473000E-19 
+Uc1= 0.00                 Kt1l= 4.0000000E-09         
+Prt= 0.00 
.CONTROL
.option noopalter 
let mc_runs = 10
let run = 0
set curplot = new
set curplottitle = "ig vs vgs plot"
set plot_out = $curplot
set p1vth0=@p1[vth0]
dowhile run <= mc_runs
if run > 0
altermod @p1[vth0]=gauss($p1vth0, 0.1, 3)
end 
tran .1n 200n
run
plot {$plot_out}.vout0
.ENDC
.END

Regards,
Fahim Khan