Hello
When I created an Infineon device model and ran a simulation, I got the message “Fatal error: realloc: can’t allocate xxx bytes.”
By the way, this error doesn’t appear unless I’m running a step simulation, but it occurs when I run a simulation using the step command.
Could someone give me some advice?
I suppose the issue might be related to X2? Well… in general, you need to assign a voltage source (25V) to Tcase to set the case temperature but not the junction temperature. But just guessing, the best is that you can upload your schematic.
Read this post and increase your trust level to upload your schematic.
Qspice Forum - New User to Basic User (File Upload) - QSPICE - Qorvo Tech Forum
I was able to run this simulation without encountering the fatal error. The model was downloaded from Infineon, and I modified the duty cycle from a fixed 0.5 to a ramping duty cycle to reduce simulation length as prevent significant current overshoot at startup.
example.IGC025S08S1.qsch (13.0 KB)
CoolGaN Transistors 80 V G3 - Spice.lib (9.5 KB)
Thank you for your reply.
Could you simulate step param simulation?
I will upload schematic later.
Oh, it weird that .step currently stopped working in this schematic. Let me report that to Mike. I didn’t pay attention you particular indicated this schematic not working in .step. Sorry for that.
Possibly, Mike will provide a permanent solution later. In the meantime, use this modified library to resolve the stack space issue when .step is used with this model.
The change involves removing +0 from a parameter, replacing dVth={dVth+0} with dVth={dVth}.
CoolGaN Transistors 80 V G3 - Spice - TempSolution.lib (9.5 KB)
Update Qspice, and this issue is resolved. The original library can now be run with .step.
01/30/2026 Implemented some optimization to the user-defined parameter compiler.
Thank you for your quick response
