Good morning,

I downloaded a model file from Ketmet for one of their caps. I'm new to Spice and would like some help and advice.

Firstly, can anyone recommend a book / site for a beginner to start creating Spice models?

From Kemet i received:

*C0402C330J5GACTU
*Temp = 25°C, Bias = 0VDC, Center Frequency = 2000000 Hz
*KEMET Model RLC Cerm
R1 3 4 0.454798362735788
R2 2 5 5
R3 1 6 99999997952
L1 1 2 1.19999996051057E-11
L2 2 3 2.27999992497008E-10
C1 4 6 3.29503302955144E-11
C2 5 6 5.99999986588955E-14
*ENDS


I'm trying to create a subcircuit and model some of the components within, so, i created this as a start:

*C0402C330J5GACTU
*Temp = 25°C, Bias = 0VDC, Center Frequency = 2000000 Hz
*KEMET Model RLC Cerm
.SUBCKT C0402C330J5GACTU 1 2
R1 3 4 0.454798362735788
R2 2 5 Rmod
R3 1 6 99999997952
L1 1 2 1.19999996051057E-11
L2 2 3 2.27999992497008E-10
C1 4 6 3.29503302955144E-11
C2 5 6 5.99999986588955E-14
.model Rmod res(R=5)
.ENDS C0402C330J5GACTU
*ENDS

Altium comes back with an error," Here is no required nominal value"

Any points / help?

Regards,

Rowland

 

it doesnt say where that error is?
You could try simplifying it, like substituting the Rmod directly first

 

Thanks.

I tried that by removing the .model Res element.

The file loads in as a sub-circuit.

Not sure when the ".model" is not working.

Regards,

Rowland

 

Good morning,

I downloaded a model file from Ketmet for one of their caps. I'm new to Spice and would like some help and advice.

Firstly, can anyone recommend a book / site for a beginner to start creating Spice models?

From Kemet i received:

*C0402C330J5GACTU
*Temp = 25°C, Bias = 0VDC, Center Frequency = 2000000 Hz
*KEMET Model RLC Cerm
R1 3 4 0.454798362735788
R2 2 5 5
R3 1 6 99999997952
L1 1 2 1.19999996051057E-11
L2 2 3 2.27999992497008E-10
C1 4 6 3.29503302955144E-11
C2 5 6 5.99999986588955E-14
*ENDS


I'm trying to create a subcircuit and model some of the components within, so, i created this as a start:

*C0402C330J5GACTU
*Temp = 25°C, Bias = 0VDC, Center Frequency = 2000000 Hz
*KEMET Model RLC Cerm
.SUBCKT C0402C330J5GACTU 1 2
R1 3 4 0.454798362735788
R2 2 5 Rmod
R3 1 6 99999997952
L1 1 2 1.19999996051057E-11
L2 2 3 2.27999992497008E-10
C1 4 6 3.29503302955144E-11
C2 5 6 5.99999986588955E-14
.model Rmod res(R=5)
.ENDS C0402C330J5GACTU
*ENDS

Altium comes back with an error," Here is no required nominal value"

Any points / help?

Regards,

Rowland

 

I don´t think .model works for simple elements like resistors

 

I don't know about the specific dialect used by Altium. The rule for LTspice which was derived from the same open source root has the following list of components that can use a ",model" card:

.MODEL -- Define a SPICE Model​

Defines a model for a diode, transistor, switch, lossy transmission line or uniform RC line​

​

I do not know of ANY SPICE dialect that allows the use of a ".model" card for resistors.

If you are looking for a textbook on SPICE modeling, you should get used to disappointment.

 

Thanks for the comments and help.

Maybe a different method?

*C0402C330J5GACTU
*Temp = 25°C, Bias = 0VDC, Center Frequency = 2000000 Hz
*KEMET Model RLC Cerm
.SUBCKT C0402C330J5GACTU 1 2
R1 3 4 0.454798362735788
R2 2 5 5
R3 1 6 99999997952
L1 1 2 1.19999996051057E-11
L2 2 3 2.27999992497008E-10
C1 4 6 3.29503302955144E-11
C2 5 6 5.99999986588955E-14
.ENDS

If i wanted to add PPM to the main capacitor (C1), what would be the best format to use, or how would i do it?

Regards,

Rowland

 

not sure what you mean. param would be my guess
.SUBCKT C0402C330J5GACTU 1 2 PARAMS: PPM=3
R1 3 4 0.454798362735788
R2 2 5 5
R3 1 6 99999997952
L1 1 2 1.19999996051057E-11
L2 2 3 2.27999992497008E-10
C1 4 6 {3.29503302955144E-11 *(1+ PPM/1e6)}
C2 5 6 5.99999986588955E-14
.ENDS

 

Ah, thank you kubeek!

And you also have explained "PARAMS" to me as well.

I've found out that Altium doesn't support .model syntax for R, C and L.

It's also based on PSPICE.

There must be a book some where?

Regards,

Rowland

 

So, moving on... i have created a Resistor, please see below.

How can i represent the 75V and that it would break with V>75V?

*ERA-3AEB204V
*Temp = 25°C, Bias = 0VDC
*Panasonic Resistor 200k 63mW 25PPM 0603 0.1% 75V
*Rowland Whiffin 22/05/2023
.SUBCKT ERA3AEB204V N1 N2 PARAMS: R1PPM=25 R1P=63e-3

R1 N2 N3 200k (TC=R1PPM/1e6 P=R1P)
L1 N1 N3 1e-20
C1 N2 N3 1e-20

.ENDS ERA3AEB204V
*ENDS

 

normally you check limiting factors like voltage, current and power dissipation in the simulation, not in the model.

 

C1 4 6 {3.29503302955144E-11 *(1+ PPM/1e6)}

When are the "{}" used? , what's their function?

Regards, R

 

Boolean?

 

I think they are required when you need to replace a value with an expression.
C1 4 6 32n is valid, but C1 4 6 32n*1.01 I think is not so you need to use {32n*1.01}