PDM MEMS Microphone Breakout Adafruit PDM MEMS Microphone Breakout is based on an STMicroelectronics MP34DTx MEMS Audio Microphone. The MP34DTx MEMS Microphones are capable of detecting acoustic waves and are manufactured using a specialized silicon micromachining process dedicated to producing audio sensors. The IC interface uses a CMOS process that allows designing a dedicated circuit able to provide a digital signal externally in PDM form.