LMV1089RLEVAL National Semiconductor, LMV1089RLEVAL Datasheet - Page 5

• 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

Adjustable Gain
The LMV1089 has two gain stages where the gain can be
adjusted to meet the requirements for the application . There
is a pre amplifier and a post amplifier gain that can be varied
independent of each other (Note 2). In most applications the
gain will be set via the I
Setting the Default Gain
The LMV1089 provides 4 pins GA0, GA1, GB0 and GB1(see
Figure 5) to set the default gain settings at power up of the
device. This is convenient for applications without a micro
controller . The default gain of the preamplifier is controlled
by the GA0 and GA1 pins and can be set by wiring those pins
to either V
values in the 12dB to 36dB range is selected. The default post
amplifier gain is set in the same way by connection the GB0
and GB1 to either V
and 15dB. Setting the gain of the preamplifier and post am-
plifier via the I
The default gain is only read and set during power up of the
device. Toggling the logic level of the enable pin (EN) will not
change the current gain setting of the part. Any gain setting
done via the I
powered down.
DD
or GND. In this way, one of the four possible
2
2
C interface will override this default gain.
C interface will remain valid until the part is
DD
or GND to select a gain between 6dB
2
C interface.
FIGURE 5. Headers for Default Gain
5
Note 1: Default value used for performance measurements.
Note 2: See the application section of LMV1089 data sheet for a more
detailed explanation of the gain budget.
GB1
GA1
0
0
1
1
0
0
1
1
TABLE 2. Default post amplifier gain
TABLE 1. Default pre amplifier gain
GB0
GA0
0
1
0
1
0
1
0
1
20dB (Note 1)
6dB (Note 1)
12dB
15dB
12dB
28dB
36dB
Gain
Gain
9dB
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