AD1981BL

Rev. A

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AC ’97 2.3 COMPATIBLE FEATURES

S/PDIF output, 20-bit data format, supporting

48 kHz and 44.1 kHz sample rates

Integrated stereo headphone amplifier

Variable sample rate audio

External audio power-down control

>90 dB dynamic range

Stereo full-duplex codec

20-bit PCM DAC

3 analog line-level stereo inputs for line-in, AUX, and CD

Mono line-level phone input

Dual MIC input with built-in programmable preamplifier

High quality CD input with ground sense

Mono output for speakerphone or internal speaker

power management support

48-lead LQFP package, Pb-free available

ENHANCED FEATURES

Stereo MIC preamplifier support

Built-in digital equalizer function for optimized

speaker sound

Full-duplex variable sample rates from 7040 Hz to

48 kHz with 1 Hz resolution

Jack sense pins for automatic output switching

microphone and external power amplifier

Low power 3.3 V operation for analog and digital supplies

Multiple codec configuration options

FUNCTIONAL BLOCK DIAGRAM

A

M

MIC1

MIC2

PHONE_IN

CD_L

CD_GND

CD_R

AUX_L

AUX_R

LINE_IN_L

MIC PREAMP

MONO_OUT

HP_OUT_L

HP

MZ

LINE_OUT_L

MZ

LINE_OUT_R

HP_OUT_R

HP

G = GAIN

A = ATTENUATION

M = MUTE

Z = HIGH Z

GA



PCM FRONT

DAC RATE

M

M

PCM L/R

ADC RATE

G

LINE_IN_R

CODEC CORE

EAPD

PLL

XTL_OUT XTL_IN SPDIF

SPDIF

TX

ID0

ID1

RESET

ADC

AND

DAC

SLOT

LOGIC

SYNC

BIT_CLK

SDATA_OUT

SDATA_IN

JS0

JS1

EAPD

AD1981BL

G

G

A

M

A

A

A

M

M

GA

M

GA

M

GA

M

GA

M

GA

M

GA

M

GA

M

GA

M

M

GA

M

M

EQ

EQ

G

G

M

G

M

G

ANALOG MIXING

CONTROL LOGIC

AC '97

CONTROL

REGISTERS

16-BIT

Σ-∆ ADC

16-BIT

Σ-∆ ADC

16-BIT

Σ-∆ ADC

16-BIT

Σ-∆ ADC

20-BIT

Σ-∆ DAC

20-BIT

Σ-∆ DAC

CD

DIFF AMP

VOLTAGE

REFERENCE

Figure 1.