Datasheet

ANALOG OUTPUT COMMON-MODE ADJUSTMENT
AUDIO DAC POWER CONTROL
TLV320AIC3007
SLOS619 – APRIL 2009 ..................................................................................................................................................................................................... www.ti.com
The output common-mode voltage and output range of the analog output are determined by an internal bandgap
reference, in contrast to other codecs that may use a divided version of the supply. This scheme is used to
reduce the coupling of noise that may be on the supply (such as 217-Hz noise in a GSM cellphone) into the
audio signal path.
However, due to the possible wide variation in analog supply range (2.7 V – 3.6 V), an output common-mode
voltage setting of 1.35 V, which would be used for a 2.7 V supply case, will be overly conservative if the supply is
actually much larger, such as 3.3 V or 3.6 V. In order to optimize device operation, the TLV320AIC3007 includes
a programmable output common-mode level, which can be set by register programming to a level most
appropriate to the actual supply range used by a particular customer. The output common-mode level can be
varied among four different values, ranging from 1.35 V (most appropriate for low supply ranges, near 2.7 V) to
1.8 V (most appropriate for high supply ranges, near 3.6 V). Note that there is also some limitation on the range
of DVDD voltage as well in determining which setting is most appropriate.
Table 4. Appropriate Settings
CM SETTING RECOMMENDED AVDD_DAC, RECOMMENDED DVDD
DRVDD
1.35 2.7 V – 3.6 V 1.525 V – 1.95 V
1.50 3.0 V – 3.6 V 1.65 V – 1.95 V
1.65 V 3.3 V – 3.6 V 1.8 V – 1.95 V
1.8 V 3.6 V 1.95 V
The stereo DAC can be fully powered up or down, and in addition, the analog circuitry in each DAC channel can
be powered up or down independently. This provides power savings when only a mono playback stream is
needed.
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