0dBto –78dB
0dBto –78dB
+
DAC_L1
DAC_R1
B0158-03
0dBto –78dB
LINE2LP_x
LINE2LM_x
0dBto –78dB
PGA_RP_x
PGA_RM_x
0dBto –78dB
PGA_LP_x
PGA_LM_x
0dBto –78dB
LINE2RP_x
LINE2RM_x
ANALOG HIGH-POWER OUTPUT DRIVERS
TLV320AIC34
SLAS538A – OCTOBER 2007 – REVISED NOVEMBER 2007
Figure 34. Detail of the Volume Control and Mixing Function Shown in Figure 33
The DAC_L/R signals are the outputs of the stereo audio DAC, which can be steered by register control based
on the requirements of the system. If mixing of the DAC audio with other signals is not required, and the DAC
output is only needed at the stereo line outputs of that partition, then it is recommended to use the routing
through path DAC_L3/R3 to the fully differential stereo line outputs. This results not only in higher-quality output
performance, but also in lower-power operation, because the analog volume controls and mixing blocks ahead of
these drivers can be powered down.
If instead the DAC analog output must be routed to multiple output drivers simultaneously (such as to
LEFT_LOP_x, LEFT_LOM_x, RIGHT_LOP_x, RIGHT_LOM_x, MONO_LOP_x, and MONO_LOM_x) or must be
mixed with other analog signals, then the DAC outputs should be switched through the DAC_L1 and DAC_R1
path. This option provides the maximum flexibility for routing of the DAC analog signals to the output drivers.
The TLV320AIC34 includes an output level control on each output driver with limited gain adjustment from 0 dB
to 9 dB. The output driver circuitry in this device is designed to provide a low-distortion output while playing
full-scale stereo DAC signals at a 0-dB gain setting. However, a higher-amplitude output can be obtained at the
cost of increased signal distortion at the output. This output level control allows the user to make this tradeoff
based on the requirements of the end equipment. Note that this output level control is not intended to be used as
a standard output volume control. It is expected to be used only sparingly for level setting, i.e., adjustment of the
full-scale output range of the device.
Each differential line output driver can be powered down independently of the others when it is not needed in the
system. When placed into power down through register programming, the driver output terminals are placed into
a high-impedance state.
The TLV320AIC34 includes eight high-power output drivers, four in each partition, with extensive flexibility in their
usage. These output drivers are individually capable of driving 40 mW each into a 16- Ω load in single-ended
configuration, and codec A can be used in pairs to drive up to 500 mW into an 8- load connected in
bridge-terminated load (BTL) configuration between two driver outputs. Codec B is not designed to drive 8- Ω
speakers.
The high-power output drivers can be configured in a variety of ways, including:
• Driving up to four fully differential output signals, using pairs of drivers
• Driving up to eight single-ended output signals
• Driving up to four single-ended output signals, with the remaining drivers driving a fixed VCM level, for
pseudo-differential stereo outputs
• Driving up to two 8- Ω speakers connected BTL between pairs of driver output terminals for codec block A
Copyright © 2007, Texas Instruments Incorporated Submit Documentation Feedback 47
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