LMV1089RLEVAL National Semiconductor, LMV1089RLEVAL Datasheet - Page 26

• 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

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AUTOMATIC CALIBRATION SETUP
A calibration test setup consists of a test room (acoustical
box) with a loudspeaker (acoustical source) driven with the
test tone sequence from
in
phone 1 and microphone 2 must be equal and the sound must
travel without any obstacle from source to both microphones.
MANUAL CALIBRATION
You can manually program the gain compensation of the two
mic inputs on the LMV1089 using the I
shows the control bits for I
responding gains. This can be easily done by doing the
following:
powering up.
settings.
1) READ contents of the I
2) Set PE pin and T7 pin to Vdd.
3) WRITE to I
Figure
13. The distances between the source and micro-
2
C register O and P to choose the calibration
Figure
2
C Register O and P with the cor-
2
C register N immediately after
12. The test setup is shown
2
C interface. Table 5
FIGURE 13. Calibration Test setup
26
The sound will travel with the limited speed of 300m/s from
the loudspeaker source to the microphones. When creating
the calibration signals this time should not be ignored, 30cm
distance will cause 1ms delay.
For an optimum automatic calibration the output level of the
microphones and preamp gain must be set so that the result-
ing signal at the output of the preamplifier is 100mV
O<3:0> control the two mics at 3kHz.
P<3:0> control the left channel gain
bits from I
EEPROM programming is complete. Now PE pin and T7 pin
should be set to GND and I
be returned to ‘1’.
4) WRITE a ‘0’ to I
5) When I
Bits O<7:4> control the two mics at 300Hz and bits
Bits P<7:4> control the right channel gain and bits
2
C register N<6:0> to I
2
C register N<7> (ready) goes high, then the
2
C register Q<7> bit (storeBar) and the
2
C register Q<7> (storeBar) should
2
C register Q<6:0>
30047235
P-P
± 6dB