MAX9814 Microphone Amplifier Module

The MAX9814 is available in the space-saving, 14-pin TDFN package. This device is specified over the -40°C to +85°C extended temperature range. MAX9814 is a low-cost, high-quality microphone amplifier with automatic gain control (AGC) and low-noise microphone bias. The device features a low-noise preamplifier, variable gain amplifier (VGA), output amplifier, microphone-bias-voltage generator and AGC control circuitry. The low-noise preamplifier has a fixed 12dB gain, while the VGA gain automatically adjusts from 20dB to 0dB, depending on the output voltage and the AGC threshold. The output amplifier offers selectable gains of 8dB, 18dB, and 28dB. With no compression, the cascade of the amplifiers results in an overall gain of 40dB, 50dB, or 60dB. A trilevel digital input programs the output amplifier gain. An external resistive divider controls the AGC threshold and a single capacitor program the attack/release times. A trilevel digital input programs the ratio of attack-to-release time. The hold time of the AGC is fixed at 30ms. The low-noise microphone-bias-voltage generator can bias most electret microphones.

Applications:

1. Bluetooth Headsets
2. Two-Way Communicators
3. High-Quality Portable Recorders
4. IP Phones/Telephone Conferencing

Technical Specifications:

1. Supply Voltage: 2.7v-5.5v @ 3mA current
2. Output: 2Vpp on 1.25V bias
3. Frequency Response: 20Hz – 20 KHz
4. Programmable Attack and Release Ratio
5. Automatic gain, selectable max from 40dB, 50dB or 60dB
6. Low Input-Referred Noise Density of 30nV/
7. Low THD: 0.04% (type)

Module pinout:

This module has 5 pins:

•  VCC: Module power supply – 2.7-5.5 V
•  GND: Ground
•  OUT: Analog data output to the microcontroller
•  Gain: Adjusting maximum module output*
• AR: Adjusting module accuracy*

Document:

• MAX9814 Microphone Module Datasheet

Package Includes:

• 1x Electret Microphone Amplifier 

Interfacing MAX9814 Module with Arduino

Source code:

// the setup routine runs once when you press reset:
void setup() {
  // initialize serial communication at 9600 bits per second:
  Serial.begin(9600);
}

// the loop routine runs over and over again forever:
void loop() {
  // read the input on analog pin 0:
  int sensorValue = analogRead(A0);
  // print out the value you read:
  Serial.println(sensorValue);
  }