TI LM25037 Not Running

I created a new model using the, “unencrypted PSpice Transient Model” from TI’s website, the model created just fine.
However, when I try and simulate with it I get the following error:
Fatal error: Error: no such function ‘sdt•x_osc1_vco•x1’
The problem occured while parsing the line:

I don’t know enough about the spice sintax to understand why I’m getting this error, any help would be

link to model

LM25037 Model Link

Open the model in text editor and edit SDT to DDT and try again.
Best regards

Pspice reference guide refer SDT as time integral of x
PSpice Reference Guide (upenn.edu)

The equivalent function in Qspice should be IDT

IDT should work in format idt(x), idx(x,y) or idx(x,y,z).
According to ivan comment, replace the line #611 with following to see if can work.

+Value {sin(6.28318*(Fcenter*V(time_a)+Frange*IDT(V(table)))+phase*(3.14159/180))}
1 Like

Thanks, that worked.
However, it’s running very slow, maybe i need to add some other .options, i’ll try that.

I made another part and changed SDT to IDT as you suggested, this also worked. But, the model is still very slow.
I still haven’t tried some .options yet.

Hi Guys-
I’m just now getting back to this design and I’m still having a lot of trouble getting the LM25037 to run.
As soon as i get one gate drive pulse it locks up, i tried setting a few initial conditions, limiting the maxstep but nothing is working. I have a feeling its all related to some with the LM25037 model, maybe there is another issue like KSKelvin pointed out.

Push_Pull 5June24.qsch (108.6 KB)
LM25037_TRANS_3.txt (30.1 KB)

Edit > Preferences : Disable “Fast (less accurate) Math”.
However, it is highly inefficient for Qspice to run the LM25037 Pspice model. After running the simulation for a few minutes, the performance significantly deteriorates, and the .qraw file quickly becomes excessively large due to the generation of numerous simulation data.

That’s what i was afraid of, thanks for looking at it.


I added a buffer or “E” with gain=1 at the LM25037 FB input. It’s in burst mode but seems to work well. ( According to the circuit design, the target level of V(out) is approximately 1kV. )

I’m not exactly sure why a buffer is needed at the FB input, but without it, the V(out) didn’t converge to the expected 1kV.

Push_Pull 5June24.qsch (86.9 KB)

Good call, EL34.
The return for V(FB) was different from X2, it must have tripped up the netlist somehow.