The signature of same-sign leptons and b-jets is a golden channel in the search for exotic production of top quarks. One of the main sources of background of same-sign leptons come from detector effects: leptons with mis-reconstructed charge and fake/non-prompt leptons. Sophisticated data-driven techniques are needed to accurately estimate them. A description of the analysis strategy and of the different techniques used to estimate the background are given here. Limits extracted for various models beyond the Standard Model are shown with the 2015 proton-proton collisions data recorded at $\sqrt{s}=13$~\TeV{} with the ATLAS detector at the Large Hadron Collider.