AD1938 Datasheet, PDF (1/32 Pages) Analog Devices – 4 ADC/8 DAC with PLL, 192 kHz, 24-Bit CODEC

4 ADC/8 DAC with PLL,
192 kHz, 24-Bit CODEC
AD1938
FEATURES
PLL generated or direct master clock
Low EMI design
108 dB DAC/107 dB ADC dynamic range and SNR
−94 dB THD + N
Single 3.3 V supply
Tolerance for 5 V logic inputs
Supports 24 bits and 8 kHz to 192 kHz sample rates
Differential ADC input
Single-ended DAC output
Log volume control with autoramp function
SPI® controllable for flexibility
Software controllable clickless mute
Software power-down
Right justified, left justified, I²S and TDM modes
Master and slave modes up to 16-channel in/out
48-lead LQFP package
APPLICATIONS
Automotive audio systems
Home Theater Systems
Set-top boxes
Digital audio effects processors
GENERAL DESCRIPTION
The AD1938 is a high performance, single-chip codec that
provides four analog-to-digital converters (ADCs) with
differential input and eight digital-to-analog converters
(DACs) with single-ended output using the Analog Devices,
Inc. patented multibit sigma-delta (Σ-Δ) architecture. An SPI
port is included, allowing a microcontroller to adjust volume
and many other parameters. The AD1938 operates from 3.3 V
digital and analog supplies. The AD1938 is available in a
48-lead (single-ended output) LQFP package. Other members
of this family include a differential DAC output and I²C® control
port version.
The AD1938 is designed for low EMI. This consideration is
apparent in both the system and circuit design architectures.
By using the on-board PLL to derive the master clock from the
LR clock or from an external crystal, the AD1938 eliminates the
need for a separate high frequency master clock and can also be
used with a suppressed bit clock. The digital-to-analog and
analog-to-digital converters are designed using the latest ADI
continuous time architectures to further minimize EMI. By
using 3.3 V supplies, power consumption is minimized, further
reducing emissions.
FUNCTIONAL BLOCK DIAGRAM
DIGITAL AUDIO
INPUT/OUTPUT
ANALOG
AUDIO
INPUTS
AD1938
SERIAL DATA PORT
ADC
ADC
ADC
ADC
DIGITAL
FILTER
SDATA
OUT
SDATA
IN
CLOCKS
TIMING MANAGEMENT
AND CONTROL
(CLOCK AND PLL)
DIGITAL
FILTER
AND
VOLUME
CONTROL
PRECISION
VOLTAGE
REFERENCE
CONTROL PORT
SPI/I²C
DAC
DAC
DAC
DAC
DAC
DAC
DAC
DAC
ANALOG
AUDIO
OUTPUTS
CONTROL DATA
INPUT/OUTPUT
Figure 1.
Rev. 0
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