The frequency response of a dual depletion p-i-n (PIN) photodiode structure is investigated. It is assumed that the light is incident on the N side and the drift region is located between the N contact and the absorption region. The numerical model takes into account the transit time and the capacitive effects and is applied to photodiodes with non-uniform illumination and linear electric field profile. With an adequate choice of the device’s structural parameters, dual depletion photodiodes can have larger bandwidths than the conventional PIN devices.