Is any model similar to LT3999 is available in Qspice library?
I couldn’t get the spice model of this IC.
LTspice model normally store in this directory :
C:\Users\%username%\AppData\Local\LTspice
If you attempt to open LT3999.sub using a text editor, you will find that it is an encrypted model. Typically, just stick with LTspice when simulating AD or LT devices, unless you have PSpice models for those devices. It save your time and you can get support from AD when using their model with LTspice. 
Note: There are unique devices (A-devices) in LTspice that are implemented differently in Qspice (now as Ã-Device and ¥-Device), and they are not directly compatible. If you have a Pspice or Generic Spice model, you can typically run that model in Qspice. But not a unique LTspice model with A-device. Even you can convert that, normally not worth for the time to do it.
Okay Understood.
Could you please tell me which models are supported by Qspice if I ask about any DC/DC Driver with PWM Control.
Or is there any option we can create that with pspice file?
Kevin, Does Qspice has Gate Driver ICs??
Currently, you have to import 3rd party model into Qspice. Generally, Qspice can work with generic spice model. For example, TI normally give Pspice and Tina-TI model for their device, and can import into Qspice (except for encrypted device).
Here is an example of TI UCC27524 Pspice model imported into Qspice as a embedded .subckt symbol. I compare its simulation result with TI Pspice example for your reference.
If you look into Qspice “Symbols & IP” browser, there is no Gate Driver IC yet. But we can guess that Qorvo will possibly add device into its library. It is not difficult to guess that Qorvo will promote their power devices with the help of Qspice. Just as Linear Technology / Analog Device with huge device library in LTspice. Qspice just launched about a year, so in short term, you still have to rely on model import.
Here is a link that Mike Engelhardt tutorial about importing 3rd party model.
https://www.qorvo.com/design-hub/videos/importing-3rd-party-models-into-qspice
I also have guideline talking about importing model and creating symbol. You can find in my “General Reference Guideline” in my Github. Click my icon and you can see the Github link.
Parent.UCC27524.qsch (10.4 KB)
UCC27524.qsym (2.8 KB)
Thanks a Ton Kelivin!!!
Its really a great help in my analysis.
Kelvin, is there any way to import this kind of encrypted file??
As far as I know, encryption is done by the simulation software, and an encrypted model will only be accessible through that software.
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I had downloaded UCC5350SBD_TRANS pspice model from TI website.
FInding some fatal errors while running the model.
Hello Kelvin,
I’m using LT1017 in my LTspice simulation, and in Qspice I took a similar comparator from Texas Instrument TLV1811 but getting convergence issues in all these type of components.
Also the generic opamp model which is available in qspice, I also used that but it’s not giving similar output as I’m getting in LTspice.
Independently TLV1811 is working fine, but in closed loop it is not converging.
I used the commands for Cshunt, trtol but still having the issue.
Can u suggest any other part which is similar to LT1017 and spice model is available.
Also, if OpAmp-Generic Rail to Rail Output OpAmp, could be configure as LT1017 for using as a comparator. Because I’m doubting that could be the issue I’m not getting the similar output as LTspice.
Is it possible to upload your schematic to the forum? There are several community members familiar with op-amps who may be able to assist. This will also help the community gain a better understanding of why Qspice sometimes encounters difficulties when running TI models. @OHara recently conducted an in-depth review of a TI model, narrowing down the issue to how the switch behaves, and this information has been forwarded to Mike for review.
Tons of convergence errors - QSPICE - Qorvo Tech Forum
If you have confidential information in your schematic, please consider whether you can reduce the simulation to a level that can be shared while still retaining the problem.