problem creating pmos caracteristics using spice model LTSPICE

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yefj

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Hello, I have tried to implement the PMOS characteristics using the model shown in the link.
I have built the model as shown in the photo bellow.
Vs=1.8V
V_SG=Vs-Vg=1.8-Vg>|Vt| => 1.8-Vg>0.39
i did a sweep on Vg from 0 till 1.8 so VSG is smaller then 0.39 at some point ,but in reality get the same current on the plot bellow.
Where did i go wrong?
from the manual shown bellow:



 

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yefj said:
Where did i go wrong?
Click to expand...
A couple of places:

For a P-MOSFET, both voltages must be negative going.
The current your simulation shows is through the substrate parasitic diode (note the direction of the diode arrow).

And if you want a set of characteristic curves, as shown in the reference manual, you need to sweep both voltage sources, as shown in the example below:
Generally you want the gate voltage to start the sweep at the MOSFETs Vgs(ths) (which is -3.2V for the transistor below).



 
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