Enables passage of a chloride ion through a transmembrane channel that opens when ATP is bound by the channel complex or one of its constituent parts on the intracellular side of the plasma membrane. [ http://en.wikipedia.org/wiki/Cystic_fibrosis_transmembrane_conductance_regulator http://www.ncbi.nlm.nih.gov/pubmed/24727426 https://enzyme.expasy.org/EC/5.6.1.6 http://www.ncbi.nlm.nih.gov/pubmed/9922375 ]