Hi I am trying to simulate a simple subcircuit model in LTSpice but I get an if function error which says
"Syntax error: function if(): requires exactly three segments"

These are the if arguments in the subcircuit code

* Function G(V(t)) - Describes the device threshold
.func G(V) = IF(V<=Vp, IF(V>=-Vn, 0, -An*(exp(-V)-exp(Vn))), Ap*(exp(V)-exp(Vp)))

* Function F(V(t),x(t)) - Describes the SV motion
.func F(V1,V2) = IF(eta*V1>=0,IF(V2>=xp,exp(-alphap*(V2-xp))*wp(V2),1),IF(V2<=(1-xn),exp(alphan*(V2+xn-1))*wn(V2),1))

Based on the IF function { IF(a, then b, else c)} both of these functions have 3 segments for each of their IF components. Is there something I'm missing out?
I have attached screenshots of the error and the IF function segments of the code for reference.

 

Welcome to AAC!
I'm only guessing, but perhaps LTS doesn't like nested IFs?

 

Hi

Here's the format for a nested If statement:

* Define Param
.param C = 1

* Define function
.func Z (A,B) {If (C<1,If(A>B,1,0),10)}

* Call function and hold result in X (this can also be a B device to output on waveform viewer)
.param X = Z(1,2)

* show result in log file
.meas Result param X

 

Thanks for your replies guys. It was the nested if issue and I got ltspice to play nice by following eetech's template.