LMV1091 Datasheet, PDF (1/20 Pages) National Semiconductor (TI) – Dual Input, Far Field Noise Suppression Microphone Amplifier

LMV1091
October 28, 2009
Dual Input, Far Field Noise Suppression Microphone
Amplifier
General Description
The LMV1091 is a fully analog dual differential input, differ-
ential output, microphone array amplifier designed to reduce
background acoustic noise, while delivering superb speech
clarity in voice communication applications.
The LMV1091 preserves near-field voice signals within 4cm
of the microphones while rejecting far-field acoustic noise
greater than 50cm from the microphones. Up to 20dB of far-
field rejection is possible in a properly configured and using
±0.5dB matched micropohones.
Part of the Powerwise™ family of energy efficient solutions,
the LMV1091 consumes only 600μA of supply current pro-
viding superior performance over DSP solutions consuming
greater than ten times the power.
The dual microphone inputs and the processed signal output
are differential to provide excellent noise immunity. The mi-
crophones are biased with an internal low-noise bias supply.
Key Specifications
■ ^{Far Field Noise Suppression Electrical *}
■ ^SNRI_E
■ ^{Supply voltage}
■ ^{Supply current}
■ ^{Standby current}
■ ^{Signal-to-Noise Ratio (Voice band)}
■ ^{Total Harmonic Distortion + Noise}
■ ^{PSRR (217Hz)}
  *FFNS_E at f = 1kHz
34dB (typ)
26dB (typ)
2.7V to 5.5V
600μA (typ)
0.1μA (typ)
65dB (typ)
0.1% (typ)
99dB (typ)
Features
■ ^{No loss of voice intelligibility}
■ ^{Low power consumption}
■ ^{Shutdown function}
■ ^{No added processing delay}
■ ^{Differential outputs}
■ ^{Adjustable 12 - 54dB gain}
■ ^{Excellent RF immunity}
■ ^{Available in a 25–bump micro SMD package}
Applications
■ ^{Mobile headset}
■ ^{Mobile and handheld two-way radios}
■ ^{Bluetooth and other powered headsets}
■ ^{Hand-held voice microphones}
System Diagram
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