This paper describes an EMC model in the frequency domain suitable for a DC-DC converter operating in Discontinuous Conduction Mode. In comparison to Continuous Conduction Mode, an additional phase appears, with voltage oscillations, which must be considered. The frequency model is presented and its implementation using LT Spice is described. It is validated in comparison with time domain simulations and measurements, for the application of a roller shutter. Finally, a fine tuning of the EMC model parameters is also presented for the industrial implementation of the converter.