adau1381 Analog Devices, Inc., adau1381 Datasheet - Page 31

• Manufacturer Part Number: adau1381
• Description: Low-noise Stereo Codec With Enhanced Recording And Playback Processing
• Manufacturer: Analog Devices, Inc.

ANALOG-TO-DIGITAL CONVERTERS
The ADAU1381 uses two 24-bit Σ-Δ analog-to-digital converters
(ADCs) with selectable oversampling rates of either 64× or 128×.
The full-scale input to the ADCs depends on AVDD1. At 3.3 V,
the full-scale input level is 1.0 V rms. Inputs greater than the
full-scale value result in clipping and distortion.
RMIC/RMICN/
LMIC/LMICN/
Figure 34. Differential Input Configuration
RMICP
MICD1
LMICP
MICD2
CM
CM
PGA
PGA
TO LEFT
ADC
TO RIGHT
ADC
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Digital ADC Volume Control
The ADC output (digital input) volume can be adjusted in
Register 16410 (0x401A), left ADC attenuator, Bits[7:0], left ADC
digital attenuator, for the left channel digital volume control and
in Register 16411 (0x401B), right ADC attenuator, Bits[7:0], right
ADC digital attenuator, for right channel digital volume control.
High-Pass Filter
A high-pass filter is used in the ADC path to remove dc offsets
and can be selected in Register 16409 (0x4019), ADC control,
Bit 5, high-pass filter select, where it can be enabled or disabled.
DIGITAL DUAL-BAND AUTOMATIC LEVEL
CONTROL (ALC)
The ADAU1381 includes an automatic level control (ALC). The
ALC adjusts the input gain continuously for a varying input signal
as dictated by the user-defined ALC settings. This allows the input
recording level to remain constant. Although this functionality
relates mainly to the record signal path, it is implemented digitally
in the sound engine.
ADAU1381