PhoneBurner does not have a national Do Not Call list but the resource to find it is here: https://telemarketing.donotcall.gov/. You'll need to signup for an account and select the area codes you are calling. Once you signup for an account you can import this list.
To read more information about it you can also look here:
Visit the PhoneBurner Blog for more information on DNC: A Comprehensive Guide to the Do-Not-Call Registry