Comparison between the level of the thermal background (solid black line), the detector saturation limit (blue dashed line), the detector read out noise (red dotted line), and the thermal background noise (black dash-dotted line). These values are obtained in LOW spectral resolution. In the L and M bands, the DIT is 125 ms and in the N band the DIT is 20 ms. In the L band, the DIT is limited by the coherence time. In the N band, the background level implies short DITs to avoid detector saturation.