LMV1088_08 Datasheet, PDF (1/26 Pages) National Semiconductor (TI) – Dual Input, Far Field Noise Suppression Microphone Amplifier with Automatic Calibration Ability

September 19, 2008
LMV1088
Dual Input, Clarisound ^TM Far Field Noise Suppression
Microphone Amplifier with Automatic Calibration Ability
General Description
The LMV1088 amplifies near-field voice signals within 4cm of
the microphones while rejecting far-field acoustic noise
greater than 0.5m from the microphones. Up to 20dB of far-
field rejection is possible in a properly configured and cali-
brated system.
Part of the Powerwise® family of energy efficient solutions,
the LMV1088 consumes 1mA of supply current while provid-
ing superior performance to DSP solutions consuming over
10 times the power.
A fast calibration during the manufacturing test process al-
lows the LMV1088 to compensate the entire microphone
system. This calibration includes mismatch in microphone
gain and frequency response, as well as acoustical path vari-
ances. The LMV1088 stores the calibration coefficients in on-
board EEPROM. The calibration is initiated by I2C command
or by pin control.
The dual microphone inputs are differential to provide excel-
lent noise immunity. The microphones are biased with an
internal low-noise bias supply.
Key Specifications
(3.3V supply, unless otherwise specified)
■ ^{Supply voltage}
■ ^{Supply current}
■ ^{Signal to noise ratio (A-weighted)}
■ ^{Total harmonic distortion}
■ ^{Noise cancellation}
■ ^PSRR
2.7V to 5.5V
1mA (typ)
60dB (typ)
0.1% (typ)
20dB (typ)
85dB (typ)
Features
■ ^{Low power consumption}
■ ^{No added processing delay}
■ ^{Automatic Calibration}
■ ^{Space-saving 36 Bump micro SMD package}
■ ^{Up to 20dB SNRI}
Applications
■ ^{Mobile handsets}
■ ^{Mobile and handheld two-way radios}
■ ^{Bluetooth and other powered headsets}
■ ^{Hand-held voice microphones}
■ ^{Portable public address systems}
Application of the LMV1088
PowerWise® is a registered trademark of National Semiconductor Corporation.
© 2008 National Semiconductor Corporation 202130
20213029
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