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Plotting gm in HSPICE...

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aryajur

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plot gm hspice

I want to plot the gm curve in HSPICE. Using the DC sweep Id vs Vgs can be plotted, so now is there a way to plot the slope of the curve also??
 

plot gm in hspice

Hi.
There is another way to plot gm of one device, however. But for equal gm (Gm) calculation of a specified structure you can measure its slope by using .measure statement and DERIV keyword (or something like that) to calculate the derivative (or slope) of your parameter 'Id/Vgs'. you can name your measurement in your netlist and write the results in output .lis file or show them in avanwaves (in .DC-> params section.)

Regards,
EZT
 

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    aryajur

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to plot gm in spice

I can't seem to make it work. I have pasted my netlist below:

Code: 
 .INCLUDE tech025u.mod
M1 0 _N_2 _N_1 _N_1 pch
V1 _N_1 _N_2  DC=1V  
V2 _N_1 0  DC=3V  

.DC V2 0 3 0.1  V1 0.3 3 0.3
.MEAS DC gm DERIV i(V2) WHEN v(_N_1)=3
.OP
.END
I cannot find a suitable condition for WHEN or AT keyword for MEASURE
Please suggest how it should be done.
 

hspice plot gm

Hi.
First of all why do you difine your node names like _N_1 why don't you just name it 1 or N1 or EZT1 or anything else you want?!! I think there's no problem in defining nodes like that in HSpice.
afterall to plot gm of a specified device you can do as follows :
.print dc gm = par('gm(m1)') v(in)
which prints gm of m1 (which is the specified device) for the sweeped dc voltage of v(in).

Regards,
EZT
 

spice plot gm

Thanks ezt I will try it out today. My node names are wierd because I am generating my Netlist using TinyCAD from sourceforge.
 

try this it will work
.Probe Gmo(M1)
notice that M1 is the name of your MOS device
you can also plot Vth Vs Vgs or any voltage by using the code below
.Probe Vth(M1)
 

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