This paper proposes first partial results for a new class of differentiators. This new differentiator is based on a recent output feedback control. This latter is based on second order sliding mode control, its main features being the finite time convergence and the robustness. This output feedback controller ensures the establishment of a "real" second order sliding mode. The differentiator provides an estimation of the time derivative of signal by taking into account the sampling feature of the differentiation computation.