there are 3 pspice for 2N5457 1. from onsemi mmbf5457=2N5457 ------------------------------------ * Model generated on Dec 6, 02 * MODEL FORMAT: PSpice .MODEL Jmmbf5457lt1 njf +VTO=-3.86852 BETA=0.000307346 LAMBDA=0.00449867 RD=15.735 +RS=49.9999 IS=1e-14 CGS=1e-12 CGD=1e-12 +PB=1 FC=0.5 KF=1e-20 AF=0.2 2. from motorola ----------------------------------- *2N5457 MCE 7-10-95 *Ref: Motorola Small-Signal Databook, Q4/94 *25V 25mA 250 ohm Dep-Mode pkg:TO-92B 3,1,2 .MODEL 2N5457 NJF(VTO=-1.8 BETA=0.00135 LAMBDA=0.001 RD=35 RS=31.5 + CGS=2.25E-12 CGD=6E-12 KF=6.5E-17 AF=0.5 ) 3. from national ----------------------------------- .model J2N5457 NJF(Beta=1.125m Betatce=-.5 Rd=1 Rs=1 Lambda=2.3m Vto=-1.372 + Vtotc=-2.5m Is=181.3f Isr=1.747p N=1 Nr=2 Xti=3 Alpha=2.543u + Vk=152.2 Cgd=4p M=.3114 Pb=.5 Fc=.5 Cgs=4.627p Kf=10.45E-18 + Af=1) * National pid=55 case=TO92 * 88-08-03 rmn BVmin=25 which one should i use?
test all using dc sweep
Hi, I've used once time 4 different models for the mosfet 2n7000.
the 4 models:
from on semiconductor a psice2 and spice3 versions
one from fairchild and one from zetex.
then i put the 4 models into single .lib then created the .olb and in the same schematic put the 4 mosfet and i did a dc sweep with primary and secondary sweep for Vgs and Vds to obtain the characteristic curves.
the result: fairchild and on models drawn the same curves except zetex model.
I know that dc analisys is not enough and still an ac analisys must be performed but the dc results gives you an idea about how similar and accurrate are the models.
many books are plotted the Id vs Vds curve with no slope after the vth of the mosfet, but being more accurate there exist an slope. In my particular case none of the 4 models showed that slope so i consider these models low accurrate at high id currents.
after all this preamble finaly i recomend to you to get in pspice the curves and use the model that exhibits slope (yes Jfet have this effect too).
Hi, I've used once time 4 different models for the mosfet 2n7000.the 4 models:
from on semiconductor a psice2 and spice3 versions
one from fairchild and one from zetex.
then i put the 4 models into single .lib then created the .olb and in the same schematic put the 4 mosfet and i did a dc sweep with primary and secondary sweep for Vgs and Vds to obtain the characteristic curves.
the result: fairchild and on models drawn the same curves except zetex model.
I know that dc analisys is not enough and still an ac analisys must be performed but the dc results gives you an idea about how similar and accurrate are the models.
many books are plotted the Id vs Vds curve with no slope after the vth of the mosfet, but being more accurate there exist an slope. In my particular case none of the 4 models showed that slope so i consider these models low accurrate at high id currents.
after all this preamble finaly i recomend to you to get in pspice the curves and use the model that exhibits slope (yes Jfet have this effect too).
Spice model for 2N5457
Looks like your third guess is most accurate. I'm referencing a university assignment where they use a similar model to the National Instruments model, you present here. This isn't proving that the model is correct, because they might just be using the same source as you, but it helps build confidence, because you know... references help.
The 2N5457 field effect transistor can be described in SPICE using the model
.MODEL 2N5457 NJF(IS=1N VT0=-1.5 BETA=1.125M LAMBDA=2.3M CGD=4PF CGS=5PF)
http://www.physics.purdue.edu/~jones105/phys536/Spring2009_Assignment_6.pdf
Looks like your third guess is most accurate. I'm referencing a university assignment where they use a similar model to the National Instruments model, you present here. This isn't proving that the model is correct, because they might just be using the same source as you, but it helps build confidence, because you know... references help.
The 2N5457 field effect transistor can be described in SPICE using the model
.MODEL 2N5457 NJF(IS=1N VT0=-1.5 BETA=1.125M LAMBDA=2.3M CGD=4PF CGS=5PF)
http://www.physics.purdue.edu/~jones105/phys536/Spring2009_Assignment_6.pdf
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