Quad Analog-to-Digital Converter (ADC)
Data Sheet
ADAU1978
FEATURES
GENERAL DESCRIPTION
Four 2 V rms differential inputs
On-chip phase-locked loop (PLL) for master clock
Low electromagnetic interference (EMI) design
The ADAU1978 incorporates four high performance, analog-to-
digital converters (ADCs) with 2 V rms capable ac-coupled inputs.
The ADCs use a multibit sigma-delta (Σ-Δ) architecture with
continuous time front end for low EMI. An I2C/serial peripheral
interface (SPI) control port is included that allows a microcontroller
to adjust volume and many other parameters. The ADAU1978
uses only a single 3.3 V supply. The part internally generates the
required digital DVDD supply. The low power architecture
reduces the power consumption. The ADAU1978 is available in
a 40-lead LFCSP package. The on-chip PLL can derive the master
clock from an external clock input or frame clock (sample rate
clock). When fed with the frame clock, it eliminates the need
for a separate high frequency master clock in the system.
106 dB analog-to-digital converter (ADC) dynamic range
Total harmonic distortion + noise (THD + N): −95 dB
Selectable digital high-pass filter
24-bit stereo ADC with 8 kHz to 192 kHz sample rates
Digital volume control with autoramp function
I2C/SPI controllable for flexibility
Software-controllable clickless mute
Software power-down
Right justified, left justified, I2S, and TDM modes
Master and slave operation modes
40-lead LFCSP package
Qualified for automotive applications
Note that throughout this data sheet, multifunction pins, such
as SCL/CCLK, are referred to either by the entire pin name or
by a single function of the pin, for example, CCLK, when only
that function is relevant.
APPLICATIONS
Automotive audio systems
Active noise cancellation systems
FUNCTIONAL BLOCK DIAGRAM
3.3V TO 1.8V
REGULATOR
DVDD
ADAU1978
AIN1P
AIN1N
AIN2P
AIN2N
AIN3P
AIN3N
AIN4P
AIN4N
IOVDD
ADC
ADC
LRCLK
BCLK
ADC
ADC
SDATAOUT1
SDATAOUT2
AGND1
AVDD2
AGND3
SCL/CCLK
SDA/COUT
2
ADDR1/CIN
ADDR0/CLATCH
I C/SPI
BG
REF
CONTROL
PLL
PD/RST
AGND2
AGND2
Figure 1.
Rev. 0
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