Electret microphones are commonly used in portable electronics because of the small size, low cost, and relatively good signal-to-noise ratio (SNR). The small package size, low operating voltage and AC performance of the OPA375 make the device a viable option for preamplifier circuits for electret microphones. The circuit shown in Figure 9-1 is a single-supply preamplifier circuit for electret microphones.

Figure 9-1 Microphone Preamplifier