Four ADCs/Eight DACs with PLL,

192 kHz, 24-Bit Codec

AD1937

Rev. 0

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FEATURES

PLL-generated clock or direct master clock

Low EMI design

112 dB DAC/107 dB ADC dynamic range and SNR

−96 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

Differential DAC output

Log volume control with autoramp function

Software-controllable clickless mute

Software power-down

Master and slave modes up to 16-channel input/output

Available in a 64-lead LQFP

AECQ-100 qualified

APPLICATIONS

Automotive audio systems

Home theater systems

Set-top boxes

Digital audio effects processors

GENERAL DESCRIPTION

The AD1937 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 differential

output, using the Analog Devices, Inc., patented multibit sigma-

microcontroller to adjust volume and many other parameters.

The AD1937 operates from 3.3 V digital and analog supplies.

The AD1937 is available in a 64-lead (differential output) LQFP.

The AD1937 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 (frame) clock or from an external crystal, the AD1937 elimi-

nates the need for a separate high frequency master clock and

can also be used with a suppressed bit clock. The DACs and

ADCs are designed using the latest Analog Devices continuous

time architecture to further minimize EMI. By using 3.3 V

supplies, power consumption is minimized and further

reduces emissions.

FUNCTIONAL BLOCK DIAGRAM

DIGITAL

FILTER

SERIAL DATA PORT

DIGITAL AUDIO

INPUT/OUTPUT

PRECISION

VOLTAGE

REFERENCE

TIMING MANAGEMENT

AND CONTROL

(CLOCK AND PLL)

CONTROL PORT

CONTROL DATA

INPUT/OUTPUT

AD1937

ADC

ADC

ADC

ADC

ANALOG

AUDIO

INPUTS

ANALOG

AUDIO

OUTPUTS

DAC

DAC

DAC

DAC

DAC

DAC

DAC

DAC

DIGITAL

FILTER

AND

VOLUME

CONTROL

SDATA

OUT

SDATA

IN

CLOCKS

Figure 1.