MAX9814 MICROPHONE AMPLIFIER MODULE

Description

The 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 programs 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 lownoise microphone-bias-voltage generator can bias most
electret microphones.
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.
Applications
● Digital Still Cameras
● Digital Video Cameras
● PDAs
● Bluetooth Headsets
● Entertainment Systems (e.g., Karaoke)
● Two-Way Communicators
● High-Quality Portable Recorders
● IP Phones/Telephone Conferencing