11-27-2013 05:50 PM
I have a spice model (txt) of an NMOS I'm trying to bring into MultiSim (file is attached). I have never worked with spice models before, so this is a first for me.
I followed the instructions I found here:
http://digital.ni.com/public.nsf/allkb/85281067A82F9DE186257AEF00654728
However, I have a few questions:
1. I only need the NMOS. So I copied everything from the top of the file until:
****************not used +CBD =0.000e+00 CBS =0.000e+00 IS =0.000e+00
+MJ =3.400e-01 N =1.000e+00 MJSW =2.300e-01
+PB =6.900e-01 TT =0.000e+00
+PBSW =6.900e-01
* ---------------------------------------------------------------------
I did NOT copy this part:
.subckt PM D G S B
+params: W=10u L=1u
M1 D G S B PM L={L} W={W} AS={2u*W} PS={2*(2u+W)} AD={2u*W} PD={2*(2u+W)}
.ends
Was that correct? Or does that section still belong to the NMOS device?
2. As part of the import process, I was supposed to verify the pin order. But I had no way of knowing for certain whether the pin order was correct or not. I used the virtual model, and it had a line of text rather than the table my imported component had. How can I tell what the correct pin order is? And what's the best way to correct it now? Should I just delete the component from the User DB and start over?
3. Once I place an instance of this component on the schematic, how do I edit the gate length and width? Specifically for just that instance, because I will place several of these, and they won't all have the same length and width.
Thanks!
11-28-2013 09:39 AM
Hi Doven,
1. You are correct, the "PBSW" is the last parameter defined in this NMOS model.
+PBSW =6.900e-01
* --------------------------------------------------
2. You can look up the NMOS in a SPICE manual it will tell you the pin out. If you look at the PMOS model in the text file, you can tell the pin order from the sub-circuit statement. Pin order starts from left to right, so D is pin 1.
.subckt PM D G S B
3. If you want to add length and width to the model, create a sub-ciruit similar to the PMOS model in the text file. You need to add these lines:
.subckt NM D G S B
M1 D G S B NM L=0.001 W=0.001
* Paste the NMOS model betwen these lines.
.ends NM
11-01-2022 02:19 PM - edited 11-01-2022 02:21 PM
Hi how do i correct this.
i copy the same schmatic file that the spice file is attached
SEE ATTACHED