small signal mosfet models in ltspice

Thread Starter

denison

Joined Oct 13, 2018
328
Hi, does anybody know if there are any small signal mosfets among the huge number of mosfet models in ltspice? In particular I am looking for a model which is in a to-92 package. Some catalogs call them j-fets and they are always in a to-92 package.
 

Audioguru

Joined Dec 20, 2007
11,248
A Jfet and a Mosfet are completely different:

1) A Jfet has a gate-source junction and is usually at its maximum drain-source conductance when the gate-source voltage is zero. A reverse bias on its gate-source reduces its conductance and can turn it off.

2) A Mosfet is usually turned off when its gate-source voltage is zero and conducts when its gate has the proper voltage polarity.
 

Thread Starter

denison

Joined Oct 13, 2018
328
A Jfet and a Mosfet are completely different:

1) A Jfet has a gate-source junction and is usually at its maximum drain-source conductance when the gate-source voltage is zero. A reverse bias on its gate-source reduces its conductance and can turn it off.

2) A Mosfet is usually turned off when its gate-source voltage is zero and conducts when its gate has the proper voltage polarity.
thanks audio guru. then I would prefer a N-mosfet in a to-92 package. this is for easy printed circuit board mounting and I only require milliamps. This is why I was looking at j-fets. The mosfets appear to be all in to-220 packages. Can you get any in a to-92 package?
So that I can complete my schematic in ltspice do you know if any of the mosfets there are small signal in a to-92 package? thanks.
 
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crutschow

Joined Mar 14, 2008
34,285
A 2N7000 is a common N-MOSFET in a TO-92 package.
It's rated at 60V, 200mA, with a 5Ω on-resistance.
It's not a standard LTspice model but below is the model you can add into the standard.mos file.

.model 2N7000 VDMOS(Rg=3 Vto=3 Rd=0 Rs=.75 Rb=.14 Kp=.17 mtriode=1.25 Cgdmax=80p Cgdmin=12p Cgs=50p Cjo=50p Is=.04p mfg=Fairchild Vds=60 Ron=5 Qg=.223n)
 
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