Anyone used IXCP10M90S ltspice model ?

[Shoog]

I am having a small problem getting a model from IXS to work. The model is

* PSpice Model Editor - Version 9.2.1

*$
*DEVICE=IXCP10M90S
.SUBCKT IXCP10M90S G A K
*** G: Gate
*** A: (+) Positive Terminal
*** K: (-) Negative Terminal
M_M1 A G K K IXC_10M90S
D_D1 K A 10M90S_D
* updated using Model Editor release 10.0.0 on 02/20/06 at 12:40
* The Model Editor is a PSpice product.
.MODEL IXC_10M90S NMOS
+ LEVEL=3
+ L=2.0000E-6
+ W=19.000E-3
+ KP=1.0547E-6
+ RS=10.000E-3
+ RD=69.978
+ VTO=-4.4878
+ RDS=1.0000E9
+ TOX=2.0000E-6
+ CGSO=526.32E-15
+ CGDO=5.2870E-9
+ CBD=85.184E-10
+ MJ=1.5000
+ PB=2.6056
+ RG=10.000E-3
+ GAMMA=0
+ KAPPA=0

.MODEL 10M90S_D D
+ BV=900
.ENDS
*$

When I placed it into a preamp model using ltspice it doesn't switch on. I thought it might be a simple layout problem so I set up a test model with just a voltage and two resistors - still wouldn't switch on.

Anyone got an opinion whats going on here.

Shoog

 

[jazbo8]

It seems to work ok here.

An externally hosted image should be here but it was not working when we last tested it.

 

[Shoog]

In your example it doesn't seem to generate a constant current which would be represented by an offset voltage in the output. Or am I missing something here.
Whats the voltage at the top of R5 ?

Can you make a 20mA CCS out of your simulation.

Shoog

 

[Shoog]

This is what I get.

 

[Shoog]

I have just managed to get it working by stripping out the .model component of the subckt.

Shoog

 

[jazbo8]

Try changing "NMOS" to "VDMOS" and remove "Level=3" from the .lib file. Here is the anode characteristic, it matches well with the datasheet:

An externally hosted image should be here but it was not working when we last tested it.

 

[Shoog]

Stripped out the level three and it works, but with residual errors.
Its working well enough for my simple needs at the moment. Getting quite a nasty distortion profile from a 2SK170 front end - surprising.

Shoog

 

[jazbo8]

Right, it isn't necessary to change "NMOS" to "VDMOS".

 

[Shoog]

Here is the distortion from the first stage 2SK170. I have lots of denegerative feedback (2K7 on the source), but I find it a little difficult to take this profile at face value.

Shoog

 

[Shoog]

It seems that even Jfets are really horrible compared to a good triode. Why do people use transistors for audio haha.

Might have to go to a LTP to make this work, but then again I might just not bother and stick with my triode preamps.

Shoog