Not only does the OpAmp amplify the signal, but it also adds a bias voltage of 1/2 VCC. When the microphone is exposed to sound sources such as a normal speaking voice a few feet away, the AUD output signal will be at about 200mV peak-to-peak. The microphone's low profile design with its port on the bottom side allows it to be mounted flush with the outer surface of your enclosure. As an omnidirectional microphone, it is capable of effectively picking up sound sources from all directions.
The SparkFun Analog MEMS Microphone Breakout operates on a supply voltage of 2.3-3.6V and has an average current consumption of 265µA. It offers a frequency range of 7Hz-36kHz, a signal-to-noise ratio of 66dBV/Pa, and a sensitivity of -44dBV/Pa in single-ended mode. It also features -3dB roll-off at 7Hz / +3dB flatness at 36kHz, an acoustic overload point of 134dB SPL, and the OPA344 provides 600Ω output impedance.
For further information and guidance on how to use the SparkFun Analog MEMS Microphone Breakout, there are several resources available, including a schematic, Eagle files, board dimensions, a hookup guide, a datasheet for the SPH8878LR5H-1, and a GitHub Hardware Repo.
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