Hi mohammad20, Welcome to EasyEDA. Please see: <https://easyeda.com/bbs_view_1983.htm> Unfortunately, right now, there is no model available for the UC384x series converters in EasyEDA. The EasyEDA ngspice model for the UC384x series converters - referred to in the above thread - is going through testing. It should be ready in early February. :)

Oh no. thank you for your help. can you tel me what software has UC3842 to run my circuit in it ? Pspice & Proteus doesnt have this model.

**LTspiceIV** <http://www.linear.com/designtools/software/#ltspice> It is a free, unlimited, mixed-mode spice simulation package from Linear Technmology. It can run any unencrypted 3rd party spice models and subcircuits. It has LT3844/5 models. The only difference between the 3842 and the 3844 is the undervoltage lockout voltages. **SIMetrix/SIMPLIS:** <http://www.simetrix.co.uk/site/index.html> has models ready to run. It has a (very generous) node limited Intro version: <http://www.simetrix.co.uk/site/demo.php> Also, have a look at this thread: <http://www.designers-guide.org/Forum/YaBB.pl?num=1374341507>

Thanks a lot about this information. I will use your advice.

Oops! My bad: the LT3844/5 models are not the same devices as the UC3844/5. :(

UC3842 was in SIMetrix software. no problem. tnQ.

The UC3843EE model is almost ready. There are some minor testing issues which I hope will be resolved sometime in the next week or two. :)

Hello, what about UC3842? it is still unusable?

Sorry but there are still some problems in converting the original model to run in ngspice. Please check back to this thread as we will post here to let everyone know when it is available.