The diode has three noise contribution, one due to the presence of the parasitic resistance rs and the other two (shot and flicker) due to the pn junction.

The thermal noise due to the parasitic resistance is:

[\begin{array}{ll} {\overline{i_{RS}^{2}} = \frac{4kT\Delta f}{RS}} & \ \end{array}]

The shot and flicker noise contributions are:

[\begin{array}{ll} {\overline{i_{d}^{2}} = 2qI_{D}\Delta f + \frac{KF \cdot I_{D}^{AF}}{f}\Delta f} & \ \end{array}]