MAX9814 Datasheet | Maxim Integrated

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 12d B gain, while the VGA gain automatically adjusts from 20d B to 0d B, depending on the output voltage and the AGC threshold. The output amplifier offers selectable gains of 8d B, 18d B, and 28d B. With no pression, the cascade of the amplifiers results in an overall gain of 40d B, 50d B, or 60d B. 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 municators - High-Quality Portable Recorders - IP Phones/Telephone Conferencing Features - Automatic Gain Control (AGC) - Three Gain Settings (40d B, 50d B, 60d B) - Programmable Attack Time - Programmable Attack and Release Ratio - 2.7V to 5.5V Supply Voltage Range - Low Input-Referred Noise Density of 30n V/√Hz - Low THD: 0.04% (typ) - Low-Power Shutdown Mode - Internal Low-Noise Microphone Bias, 2V - Available in the Space-Saving, 14-Pin TDFN (3mm x 3mm) Package - -40°C to +85°C Extended Temperature Range Ordering Information appears at end of data sheet. Simplified Block Diagram 2.7V TO 5.5V RMICBIAS MICBIAS CIN MICIN LOW-NOISE REFERENCE SHDN VDD AGC LNA +12d B VGA +20d B/0d B GAIN...