MAX9814 Microphone Amplifier Module with Automatic Gain Control (AGC)

Product Description

The MAX9814 Microphone Amplifier Module is a low-cost, high-performance audio amplifier board designed specifically for electret microphones. It comes fully assembled and tested, with a 20Hz–20KHz electret microphone pre-soldered on the board.

At the heart of the module is the MAX9814, a specialized chip designed for amplifying electret microphones in applications where sound levels are unpredictable. The built-in Automatic Gain Control (AGC) automatically adjusts amplification levels, reducing loud sounds to prevent clipping while boosting quieter sounds for clear detection and recording.

This module is ideal for projects involving sound detection, voice recording, alarm systems, audio monitoring, and microcontroller-based applications.

Key Features

• Built-in Automatic Gain Control (AGC)

• Selectable maximum gain: 40dB / 50dB / 60dB

• Programmable Attack/Release Ratio:

  • Default: 1:4000

  • Optional: 1:2000 or 1:500

• Low input-referred noise density: 30 nV/√Hz

• Low Total Harmonic Distortion (THD): 0.04% (typical)

• Built-in 2V low-noise microphone bias

• Low-power shutdown mode

• Fully assembled with onboard electret microphone

• Suitable for microcontroller and ADC interfacing

Technical Specifications

Parameter Value

Operating Voltage 2.7V – 5.5V

Operating Current 3mA

Output Signal 2Vpp (on 1.25V DC bias)

Frequency Response 20Hz – 20KHz

Maximum Gain Options 40dB / 50dB / 60dB

Input Noise Density 30 nV/√Hz

THD 0.04% (typical)

Temperature Range -40°C to +85°C

Output Information

• Output amplitude: 2V peak-to-peak

• DC bias: 1.25V

• Compatible with 3.3V ADC inputs

• For Line-In applications, use a 1µF–100µF series blocking capacitor (100µF recommended for best audio quality)

Applications

• Sound detection systems

• Voice-activated projects

• Audio recording devices

• Noise monitoring systems

• Alarm systems

• Microcontroller-based audio projects