LMV1089RLEVAL National Semiconductor, LMV1089RLEVAL Datasheet - Page 12

• 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

www.national.com
Automatic Calibrating of a System
Containing the LMV1089
The full automatic calibration should only be required once,
when the product containing the LMV1089 has completed
manufacture, and prior to application packaging. The product
containing the LMV1089 will be calibrated to the micro-
phones, the microphone spacings, and the acoustical prop-
erties of the final manufactured product containing the
LMV1089.
The compensation or calibration technology is achieved via
memory stored coefficients when the Far Field Noise Sup-
pression (FFNS) circuitry activates the calibration sequence.
The purpose of the calibration sequence is to choose the op-
timized coefficients for the FFNS circuitry for the given micro-
Both the CAL pin and the PE pin can be pulled up by con-
necting a jumper at the corresponding header J19 and J18.
The Pin 2 of those header can be controlled by a applying a
valid logical level to these pins ('Low' < 0.4*I
0.6*I
Note: Pin 1 of the headers J18 and J19 are connected to V
Automatic Calibration Setup
AUTOMATIC CALIBRATION VIA CAL PIN
To initiate the automatic calibration via the CAL pin, the fol-
lowing procedure is required:
•
From the initial condition where both PE and CAL are at
'low' level
2
CV
DD
).
FIGURE 14. Location of CAL pin and PE pin
2
CV
DD
DD
.
or 'High' >
12
phones, spacing, and acoustical environment of the product
containing the LMV1089
A basic calibration can be performed with a single 1kHz tone
(see section Performing a One Tone Calibration), however to
take full advantage of this calibration feature a three tone cal-
ibration (see the section Performing a Three Tone Calibra-
tion) is preferred .
The automatic calibration process can be initiated from either
a digital interface CALIBRATE pin (CAL / J19 see Figure 14)
or via the I
The logic level at the PROGRAM ENABLE (PE) pin deter-
mines if the result of the calibration is volatile or permanent.
To make the result of the calibration permanent (stored in the
EEPROM) the PROGRAM ENABLE pin (PE / J18 see Figure
14) must be high during the automatic calibration process.
•
•
•
•
•
•
•
A tone may be applied prior to the rising of CAL and PE. Sig-
nals applied to the microphone inputs before rising of CAL
and PE are ignored by the calibration system.
Bring PE to a 'high' level (enable EEprom write)
Bring CAL to a 'high' level to start Calibration
Apply Audio stimulus (single tone 1kHz or three tone
sequence as described in Performing a One Tone
Calibration and Performing a Three Tone Calibration)
Hold CAL 'high' for at least 790ms
Remove Audio stimulus
Bring CAL to a 'low' level to stop Calibration
Bring PE to a 'low' level (disable EEprom write)
2
C interface.
30060606