lmv1091tmx-nopb National Semiconductor Corporation, lmv1091tmx-nopb Datasheet

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lmv1091tmx-nopb

Manufacturer Part Number
lmv1091tmx-nopb
Description
Dual Input, Far Field Noise Suppression Microphone Amplifier
Manufacturer
National Semiconductor Corporation
Datasheet
© 2009 National Semiconductor Corporation
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.
System Diagram
300922
LMV1091
Key Specifications
  *FFNS
Features
Applications
Far Field Noise Suppression Electrical *
SNRI
Supply voltage
Supply current
Standby current
Signal-to-Noise Ratio (Voice band)
Total Harmonic Distortion + Noise
PSRR (217Hz)
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
Mobile headset
Mobile and handheld two-way radios
Bluetooth and other powered headsets
Hand-held voice microphones
E
E
at f = 1kHz
30092240
October 28, 2009
www.national.com
2.7V to 5.5V
600μA (typ)
0.1μA (typ)
34dB (typ)
26dB (typ)
65dB (typ)
99dB (typ)
0.1% (typ)

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lmv1091tmx-nopb Summary of contents

Page 1

... 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. System Diagram © 2009 National Semiconductor Corporation LMV1091 Key Specifications ■ Far Field Noise Suppression Electrical * ■ ...

Page 2

Typical Application FIGURE 1. Typical Dual Microphone Far Field noise Cancelling Application www.national.com 2 30092215 ...

Page 3

... SMD Marking Top View X = Plant Code YY = Date Code TT = Die Traceability ZA4 = LMV1091TM Order Number Package LMV1091TM 25 Bump µSMD LMV1091TMX 25 Bump µSMD 25ump micro SMD package Top View Order Number LMV1091TM See NS Package Number TMD25AAA 30092231 Ordering Information Package Drawing Device Marking ...

Page 4

Bump Number Pin Name A1 MIC BIAS A2 MIC2+ A3 MIC2– A4 MIC1+ A5 MIC1– B1 MODE0 B2 MODE1 B3 GA0 B4 GA1 B5 GND C1 MUTE2 C2 GB0 GA2 C5 REF D1 MUTE1 D2 GB1 D3 ...

Page 5

Absolute Maximum Ratings If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Supply Voltage Storage Temperature Power Dissipation (Note 3) ESD Rating (Note 4) ESD Rating (Note 5) CDM Junction Temperature ...

Page 6

I Shut Down Current SD T Turn-On Time (Note Turn-Off Time (Note 9) OFF V Logic High Input Threshold IH V Logic Low Input Threshold IL Electrical Characteristics 5.0V Unless otherwise specified, all limits guaranteed for T ...

Page 7

Symbol Parameter V Logic High Input Threshold IH V Logic Low Input Threshold IL Note 1: “Absolute Maximum Ratings” indicate limits beyond which damage to the device may occur, including inoperability and degradation of device reliability and/or performance. Functional operation ...

Page 8

Test Methods FAR FIELD NOISE SUPPRESSION (FFNS For optimum noise suppression the far field noise should broadside array configuration from the two microphones (see Figure 8). Which means the far field sound source is equidistance from the ...

Page 9

Measuring Noise and SNR The overall noise of the LMV1091 is measured within the fre- quency band from 10Hz to 22kHz using an A-weighted filter. For the signal to noise ratio (SNR) the signal level at the out- put is ...

Page 10

Typical Performance Characteristics = 18mV , f = 1kHz, pass through mode, Pre Amp gain = 20dB, Post Amp gain = 6dB, R P-P THD+N vs Frequency Mic1 = AC GND, Mic2 = 36mV Noise Canceling Mode THD+N vs Frequency ...

Page 11

THD+N vs Input Voltage f = 1kHz Mic1 Pass Through Mode PSRR vs Frequency Pre Amp Gain = 20dB, Post Amp Gain = 6dB V = 100mV , Mic1 = Mic2 = AC GND RIPPLE P-P Mic1 Pass Through Mode ...

Page 12

Signal-to-Noise Ratio Electrical vs Frequency 12 30092269 ...

Page 13

Application Data INTRODUCTION The LMV1091 is a fully analog single chip solution to reduce the far field noise picked up by microphones in a communi- FIGURE 3. Simplified Block Diagram of the LMV1091 The output signal of the microphones is ...

Page 14

Example 1 An application using microphones with 50mV output voltage, and a baseband chip after the LMV1091 with 1.5V maximum input voltage. P-P For optimum noise performance, the gain of the input stage should be set to the maximum. 1. ...

Page 15

Pre-Amp/Post-Amp Gains The Pre-amplifier gain of the LMV1091TM can be controlled using the GA0-GA3 pins. See table 2 below for Pre-amplifier GA3 GA2 ...

Page 16

Mute Section Mic 1 and Mic 2 can be muted independently, using the Mute 1 and Mute 2 pins. See Table 5 for control settings. Mute Microphone Placement Because the LMV1091 is a microphone array ...

Page 17

Low-Pass Filter At The Output At the output of the LMV1091 there is a provision to create order low-pass filter (only enabled in 'Noise Cancelling' mode). This low-pass filter can be used to compensate for the change ...

Page 18

Revision History Rev Date 1.0 10/28/09 www.national.com Description Initial released. 18 ...

Page 19

Physical Dimensions inches (millimeters) unless otherwise noted 25 Bump micro SMD Technology NS Package Number TMD25AAA X = 2015mm X = 2015mm X = 600mm www.national.com ...

Page 20

... National Semiconductor and the National Semiconductor logo are registered trademarks of National Semiconductor Corporation. All other brand or product names may be trademarks or registered trademarks of their respective holders. ...

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