adau1461 Analog Devices, Inc., adau1461 Datasheet - Page 28

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

ADAU1461
Analog Microphone Inputs
For microphone inputs, configure the part in either stereo
pseudo-differential mode or stereo full differential mode.
The LINN and LINP pins are the inverting and noninverting
inputs for the left channel, respectively. The RINN and RINP
pins are the inverting and noninverting inputs for the right
channel, respectively.
For a differential microphone input, connect the positive signal
to the noninverting input of the PGA and the negative signal to
the inverting input of the PGA, as shown in Figure 33. The PGA
settings are controlled with Register R8 (left differential input
volume control register, Address 0x400E) and Register R9 (right
differential input volume control register, Address 0x400F). The
PGA must first be enabled by setting the RDEN and LDEN bits.
The PGA can also be used for single-ended microphone inputs.
Connect LINP and/or RINP to the CM pin. In this configura-
tion, the signal connects to the inverting input of the PGA,
LINN and/or RINN, as shown in Figure 34.
MICROPHONE
MICROPHONE
MICROPHONE
MICROPHONE
Figure 34. Stereo Single-Ended Microphone Configuration
Figure 33. Stereo Differential Microphone Configuration
RIGHT
RIGHT
LEFT
LEFT
2kΩ
2kΩ
2kΩ
2kΩ
MICBIAS
MICBIAS
RINN
RINP
LINN
LINP
RINP
RINN
LINN
LINP
CM
RIGHT
RIGHT
LEFT
PGA
PGA
LEFT
–12dB TO
–12dB TO
PGA
PGA
+35.25dB
+35.25dB
–12dB TO
–12dB TO
+35.25dB
+35.25dB
ADAU1461
ADAU1461
RDBOOST[1:0]
LDBOOST[1:0]
LDBOOST[1:0]
RDBOOST[1:0]
0dB/20dB
0dB/20dB
0dB/20dB
0dB/20dB
MUTE/
MUTE/
MUTE/
MUTE/
Rev. 0 | Page 28 of 88
Analog Line Inputs
Line input signals can be accepted by any analog input. It is
possible to route signals on the RINN, RINP, LINN, and LINP
pins around the differential amplifier to their own amplifier and
to use these pins as single-ended line inputs by disabling the
LDEN and RDEN bits (Bit 0 in Register R8, Address 0x400E,
and Bit 0 in Register R9, Address 0x400F). Figure 35 depicts a
stereo single-ended line input using the RINN and LINN pins.
The LAUX and RAUX pins are single-ended line inputs. They
can be used together as a stereo single-ended auxiliary input, as
shown in Figure 35. These inputs can bypass the input gain
control, mixers, and ADCs to directly connect to the output
playback mixers (see auxiliary bypass in Figure 32).
Figure 35. Stereo Single-Ended Line Input with Stereo Auxiliary Bypass
RIGHT LINE
RIGHT AUX
LEFT LINE
LEFT AUX
INPUT
INPUT
INPUT
INPUT
RAUX
LAUX
RINN
LINN
AUXILIARY
BYPASS
–12dB TO +6dB
–12dB TO +6dB
ADAU1461
RINNG[2:0]
LINNG[2:0]