adau1461 Analog Devices, Inc., adau1461 Datasheet - Page 27

• Manufacturer Part Number: adau1461
• Description: Sigmadsp Stereo, Low Power, 96 Khz, 24-bit Audio Codec With Integrated Pll Adau1461
• Manufacturer: Analog Devices, Inc.

RECORD SIGNAL PATH
INPUT SIGNAL PATHS
The ADAU1461 can accept both line level and microphone
inputs. The analog inputs can be configured in a single-ended
or differential configuration. There is also an input for a digital
microphone. The analog inputs are biased at AVDD/2. Unused
input pins should be connected to CM.
Each of the six analog inputs has individual gain controls (boost
or cut). The input signals are mixed and routed to an ADC. The
mixed input signals can also bypass the ADCs and be routed
directly to the playback mixers. Left channel inputs are mixed
before the left ADC; however, it is possible to route the mixed
analog signal around the ADC and output it into a left or right
output channel. The same capabilities apply to the right channel
and the right ADC.
JACKDET/MICIN
RAUX
LAUX
RINN
LINN
RINP
LINP
RDVOL[5:0]
LDVOL[5:0]
PGA
PGA
ALC
CONTROL
ALC
CONTROL
–12dB TO
+35.25dB
–12dB TO
+35.25dB
ALCSEL[2:0]
ALCSEL[2:0]
RDBOOST[1:0]
LDBOOST[1:0]
RINNG[2:0]
LINNG[2:0]
LINPG[2:0]
RINPG[2:0]
MX1AUXG[2:0]
MX2AUXG[2:0]
–12dB TO +6dB
–12dB TO +6dB
MUTE/0dB/20dB
MUTE/0dB/20dB
–12dB TO +6dB
–12dB TO +6dB
–12dB TO +6dB
–12dB TO +6dB
Figure 32. Record Signal Path
Rev. 0 | Page 27 of 88
(LEFT RECORD
Signals are inverted through the PGAs and the mixers. The
result of this inversion is that differential signals input through
the PGA are output from the ADCs at the same polarity as they
are input. Single-ended inputs that pass through the mixer but
not through the PGA are inverted. The ADCs are noninverting.
The input impedance of the analog inputs varies with the gain
of the PGA. This impedance ranges from 1.7 kΩ at the 35.25 dB
gain setting to 80.4 kΩ at the −12 dB setting. This range is shown
in Figure 25.
(RIGHT RECORD
MIXER 1
MIXER)
AUXILIARY
BYPASS
MICROPHONE
MIXER 2
INTERFACE
MIXER)
(TO PLAYBACK
DIGITAL
(TO PLAYBACK
OUTPUT
MIXER 2
OUTPUT
MIXER 1
MIXER)
MIXER)
RIGHT
LEFT
ADC
ADC
MICIN LEFT
MICIN RIGHT
INSEL
INSEL
DECIMATOR/
ADAU1461
DIGITAL
VOLUME
ALC/