In photoacoustic (PA) spectroscopy, the signal is inversely proportional to the resonant cell volume. This favorable scaling behavior has provoked in recent years a growing interest in the miniaturization of PA cells. Due to dimension downscaling, technological constraints, and preliminary design choices, the modeling hypotheses used at the macro-scale are no longer valid. Here, a new model adapted to miniaturized and integrated PA ( $$\upmu $$ μ -PA) sensors is presented. The coupled model takes advantage of commercial software to address, respectively, (i) the electromagnetic mode propagation in the waveguide, (ii) the mid-IR light illumination of the chamber and its interaction with the molecules of interest, and (iii) the creation and propagation of acoustic waves in the cell. The model has been used to confirm the validity of the choice of the differential Helmholtz resonator principle and to provide a prototype $$\upmu $$ μ -PA cell geometry. It is shown that, in spite of the specific issues inherent to miniaturization and integration, in particular, the strong divergence of the light beam and the crucial influence of viscothermal dissipation processes, the $$\upmu $$ μ -PA sensor produces a pressure signal compatible with the next generation of resonant microphone technology. The model will be further improved when measurements performed on the prototype currently in fabrication are available.