Pre-Amplifier for MEMS Microphone

This is a low-cost, small-size audio pre-amplifier for MEMS microphone, OPAMP-based circuit amplifies the low-level analog signal coming from MEMS microphone to the desired level required for the next stage which is an audio amplifier, basically microphone level to line level. Resistor R4 and R7 are used to generate a voltage reference to bias the input common-mode voltage of the op-amp at VCC/2, C7, C8, and R7 help to reduce power supply noise.

Key Features

• Supply 3.3V
• Very Low Noise Output
• On-Board Power LED
• Dual Microphone Option (Onboard or External Microphone)
• The OPAMP gain is set to 32 (Gain = 1+R2/R3)
• PCB Dimensions 27.78 x 14.29 mm