Rainbow Electronics MAX9814 - Manual

General 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 thresh-
old. 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 low-noise microphone-bias-
voltage generator can bias most electret microphones.
The MAX9814 is available in the space-saving 12-bump
UCSP™ (1.5mm x 2mm) and 14-pin TDFN packages.
This device is specified over the -40°C to +85°C
extended temperature range.
Applications
Features
♦ Automatic Gain Control (AGC)
♦ Three Gain Settings (40dB, 50dB, 60dB)
♦ Programmable Attack Time
♦ Programmable Attack and Release Ratio
♦ 2.7V to 5.5V Supply Voltage Range
♦ Low Input-Referred Noise Density of 30nV/√Hz
♦ Low THD: 0.04% (typ)
♦ Low-Power Shutdown Mode
♦ Internal Low-Noise Microphone Bias, 2V
♦ Available in the Space-Saving 12-Bump UCSP
(1.5mm x 2mm) and TDFN (3mm x 3mm)
Packages
♦ -40°C to +85°C Extended Temperature Range
MAX9814
Microphone Amplifier with AGC and
Low-Noise Microphone Bias
________________________________________________________________ Maxim Integrated Products 1
Ordering Information
Simplified Block Diagram
LOW-NOISE
REFERENCE
AGC
2.7V TO 5.5V
LNA
+12dB
VGA
+20dB/0dB
GAIN
+8/+18/
+28dB
MICBIAS
R MICBIAS
MICIN OUT
C OUT
GND
C IN
V DD SHDN
MAX9814
PART TEMP RANGE
PIN-
PACKAGE PKG
CODE
MAX9814EBC+T -40°C to +85°C 12 UCSP-12 B12-3
MAX9814ETD+T -40°C to +85°C 14 TDFN-14 T1433-2
19-0764; Rev 0; 3/07
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
+ Denotes a lead-free package.
Pin Configurations appear at end of data sheet.
UCSP is a trademark of Maxim Integrated Products, Inc.
EVALUATION KIT
AVAILABLE
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