LMV1089RLEVAL National Semiconductor, LMV1089RLEVAL Datasheet - Page 29

• Manufacturer Part Number: LMV1089RLEVAL
• Description: BOARD EVALUATION LMV1089
• Manufacturer: National Semiconductor
• Series: PowerWise®r

Specifications of LMV1089RLEVAL

• Main Purpose: Audio, Microphone Amp
• Embedded: No
• Utilized Ic / Part: LMV1089
• Primary Attributes: Dual Input, Single Output
• Secondary Attributes: Graphical User Interface, I²C Interface
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

For the signal to noise ratio (SNR) the signal level at the out-
put is measured with a 1kHz input signal of 18mV
A-weighted filter. This voltage represents the output voltage
of a typical electret condenser microphone at a sound pres-
sure level of 94dB SPL, which is the standard level for these
measurements. The LMV1089 is programmed for 26dB of to-
FIGURE 17. A-Weighted Filter
FIGURE 18. Noise Measurement Setup
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P-P
using an
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MEASURING NOISE AND SNR
The overall noise of the LMV1089 is measured within the fre-
quency band from 10Hz to 22kHz using an A-weighted filter.
The Mic+ and Mic- inputs of the LMV1089 are AC shorted
between the input capacitors, see
tal gain (20dB preamplifier and 6dB postamplifier) with only
Mic1 or Mic2 used. (See also I
The input signal is applied differentially between the Mic+ and
Mic-. Because the part is in Pass Through mode the low-pass
filter at the output of the LMV1089 is disabled.
2
C Compatible Interface).
Figure
18.
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