Playback Signal Path; Output Signal Paths - Analog Devices ADAU1961 Manual

PLAYBACK SIGNAL PATH

LEFT INPUT MIXER
RIGHT INPUT MIXER
LAUX
LEFT DAC
RIGHT DAC
LEFT INPUT MIXER
RIGHT INPUT MIXER
RAUX
LEFT DAC
RIGHT DAC

OUTPUT SIGNAL PATHS

The outputs of the ADAU1961 can be configured as a variety of
differential or single-ended outputs. All analog output pins are
capable of driving headphone or earpiece speakers. There are
selectable output paths for stereo signals or a downmixed mono
output. The line outputs can drive a load of at least 10 kΩ or can
be put into HP mode to drive headphones or earpiece speakers.
The analog output pins are biased at AVDD/2.
With a 0 dBFS digital input and AVDD = 3.3 V, the full-scale
output level is 920 mV rms.
Signals are inverted through the mixers and volume controls.
The result of this inversion is that the polarity of the differential
outputs and the headphone outputs is preserved. The single-
ended mono output is inverted. The DACs are noninverting.
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MX3G1[3:0]
–15dB TO +6dB
MX3G2[3:0]
–15dB TO +6dB
MX3AUXG[3:0]
–15dB TO +6dB
MX3LM
MX3RM
(MONO MIXER)
MX4G1[3:0]
–15dB TO +6dB
MX4G2[3:0]
–15dB TO +6dB
MX4AUXG[3:0]
–15dB TO +6dB
MX4LM
MX4RM
MIXER 3
(LEFT
PLAYBACK
MIXER)
MIXER 5
(LEFT L/R
PLAYBACK
MIXER)
MX5G3[1:0]
MX6G3[1:0]
MX7[1:0]
MIXER 7
MIXER 6
(RIGHT L/R
PLAYBACK
MX5G4[1:0]
MIXER)
MX6G4[1:0]
MIXER 4
(RIGHT
PLAYBACK
MIXER)
Figure 43. Playback Signal Path
Routing Flexibility
The playback path contains five mixers (Mixer 3 to Mixer 7)
that perform the following functions:
•
Mix signals from the record path and the DACs.
•
Mix or swap the left and right channels.
•
Mix a mono signal or generate a common-mode output.
Mixer 3 and Mixer 4 are dedicated to mixing signals from the
record path and the DACs. Each of these two mixers can accept
signals from the left and right DACs, the left and right input
mixers, and the dedicated channel auxiliary input. Signals
coming from the record path can be boosted or cut before the
playback mixer.
For example, the MX4G2[3:0] bits set the gain from the output
of Mixer 2 (right record channel) to the input of Mixer 4, hence
the naming convention.
Signals coming from the DACs have digital volume attenu-
ation controls set in Register R20 (left input digital volume
register, Address 0x401A) and Register R21 (right input digital
volume register, Address 0x401B).
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ADAU1961
LHPVOL[5:0]
LHP
–57dB TO +6dB
LOUTVOL[5:0]
LOUTP
–57dB TO +6dB
–1 LOUTN
MONOVOL[5:0]
MONOOUT
–57dB TO +6dB
–1 ROUTN
ROUTVOL[5:0]
ROUTP
–57dB TO +6dB
RHPVOL[5:0]
RHP
–57dB TO +6dB