ltspice - getting "Unknown subcircuit" when using a .model directive

[ledtester]

I'm trying to use a .model directive in my schematic, but I'm getting an "Unknown subcircuit" error when I try to run the simulation.

I can get it to work if I use a .subckt directive instead. I've attached the ltspice file (it's a very simple circuit.)

What am I doing wrong?

Here is the complete .asc file:

Version 4
SHEET 1 1520 2404
WIRE -560 -32 -688 -32
WIRE -448 -32 -560 -32
WIRE -448 80 -448 48
WIRE -688 96 -688 -32
WIRE -560 160 -560 -32
WIRE -496 160 -560 160
WIRE -688 224 -688 176
WIRE -560 224 -688 224
WIRE -448 224 -448 176
WIRE -448 224 -560 224
WIRE -560 240 -560 224
FLAG -560 240 0
SYMBOL nmos -496 80 R0
SYMATTR InstName M1
SYMATTR Value 2N9999
SYMATTR Prefix X
SYMBOL voltage -688 80 R0
WINDOW 123 0 0 Left 2
WINDOW 39 0 0 Left 2
SYMATTR InstName V1
SYMATTR Value 5
SYMBOL res -464 -48 R0
SYMATTR InstName R1
SYMATTR Value 1k
TEXT -688 296 Left 2 !.tran 0 0.001 0 1u
TEXT -688 360 Left 2 !.model 2N9999 VDMOS(Rg=3 Vto=1.6 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=2 Qg=1.5n)

[liquibyte]

I tried for awhile with no luck myself so I decided to look for the spice line itself.  Minus the 2N9999 part, the following line is exact and I found it here

Code: [Select]

.model 2N7002 VDMOS(Rg=3 Vto=1.6 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=2 Qg=1.5n)
Seeing that, I added a 2N7002 to the simulation and it works though I don't understand what you're trying to achieve with it.

Edit: just for fun, here's the models from Fairchild.

[bson]

Get rid of the "prefix x".

[eetech00]

Delete the NMOS device then add it back in

If you change the prefix to "X", LTspice searches for a .subckt definition.
Since you are using a .model statement, do not change the prefix to "X".

[ledtester]

Thanks everyone - blanking out the PREFIX for the device worked.

I've had a lot of trouble modifying the ltspice lib files to include the 2n7000 definition, so I wanted to figure out how to hard code a device definition into the schematic file using a .model directive.