adau1361 Analog Devices, Inc., adau1361 Datasheet - Page 29

• Manufacturer Part Number: adau1361
• Description: Stereo, Low Power, 96 Khz, 24-bit Audio Codec With Integrated Pll
• Manufacturer: Analog Devices, Inc.

Microphone Bias
The MICBIAS pin provides a voltage reference for electret analog
microphones. The MICBIAS voltage is set in Register R10
(record microphone bias control register, Address 0x4010). In
this register, the MICBIAS output can be enabled or disabled.
Additional options include high performance operation and a
gain boost. The gain boost provides two different voltage biases:
0.65 × AVDD or 0.90 × AVDD. When enabled, the high perfor-
mance bit increases supply current to the microphone bias
circuit to decrease rms input noise.
The MICBIAS pin can also be used to cleanly supply voltage to
digital microphones or analog microphones with separate
power supply pins.
ANALOG-
The ADAU1361 uses two 24-bit Σ-Δ analog-to-digital converters
(ADCs) with selectable oversampling rates of 64× or 128×
(selected by Bit 3 in Register R17, Address 0x4017).
TO-DIGITAL CONVERTERS
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ADC Full-Scale Level
The full-scale input to the ADCs (0 dBFS) depends on AVDD.
At AVDD = 3.3 V, the full-scale input level is 1.0 V rms. The
full-scale input level scales linearly with the level of AVDD.
For single-ended and pseudo-differential signals, the full-scale
value corresponds to the signal level at the pins, 0 dBFS.
Full differential full-scale input is measured after the differential
amplifier, which corresponds to −6 dBFS at each pin.
Signal levels above the full-scale value cause the ADCs to clip.
Digital ADC Volume Control
The digital ADC volume can be attenuated in Register R20 (left
inp
(right input digital volume reg
High-Pass Filter
By default, a high-pass filter is used in the ADC path to remove
dc offsets; this filter can be enabled or disabled in Register R19
(ADC control register, Address 0x4019). At f
corner frequency of this high-pass filter is 2 Hz.
ut digital volume register, Address 0x401A) and Register R21
ister, Address 0x401B).
S
= 48 kHz, the
ADAU1361