Hi Steven,
The UCD family of parts are currently not supported by SPICE models.
Best regards,
Nikhil
Nikhil Gupta
Power Modeling Engineer
WEBENCH Design Center
All our existing models can be found here: www.ti.com.spicerack. From your message it looks like you have already visited this site. We have a lot of models available for analog converters/controllers which you can find here. Unfortunately, we do not have any spice models for digital controllers.
- Nikhil
Some of the digital controllers are supported through the Digital Fusion Software. Although it does not provide SPICE simulation capability, it does provide help to configure the devices and setting up your systaem along with sample waveforms. Maybe this will help you with your problem.
http://www.ti.com/product/ucd7231#softTool