LMV1091TM/NOPB National Semiconductor, LMV1091TM/NOPB Datasheet - Page 9

• Manufacturer Part Number: LMV1091TM/NOPB
• Description: IC AMP MIC DUAL INPUT 25USMD
• Manufacturer: National Semiconductor
• Series: PowerWise®r
• Type: Class ABr

Specifications of LMV1091TM/NOPB

• Output Type: 2-Channel (Stereo)
• Voltage - Supply: 2.7 V ~ 5.5 V
• Features: Differential Inputs, Microphone, Shutdown
• Mounting Type: Surface Mount
• Package / Case: 25-MicroSMD
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Max Output Power X Channels @ Load: -
• Other names: LMV1091TMTR

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 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 LMV1091 is programmed for 26dB of to-
FIGURE 11: Noise Measurement Setup
P-P
using an
9
The Mic+ and Mic- inputs of the LMV1091 are AC shorted
between the input capacitors, see Figure 11.
tal gain (20dB preamplifier and 6dB postamplifier) with only
Mic1 or Mic2 used.
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 LMV1091 is disabled.
30092211
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