®
a
AC ’97 SoundMAX Codec
AD1981B
FEATURES
Mono Output for Speakerphone or Internal Speaker
Power Management Support
AC ’97 2.3 COMPATIBLE FEATURES
S/PDIF Output, 20 Bits Data Format, Supporting
48 kHz and 44.1 kHz Sample Rates
Integrated Stereo Headphone Amplifier
Variable Sample Rate Audio
External Audio Power-Down Control
Greater than 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 Preamp
High Quality CD Input with Ground Sense
48-Lead LQFP Package, Lead-Free Available
ENHANCED FEATURES
Stereo MIC Preamps 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 Provide Automatic Output Switching
Software Programmed VREFOUT Output for Biasing
Microphone and External Power Amp
Split Power Supplies: 3.3 V Digital and 5 V Analog
Multiple Codec Configuration Options
FUNCTIONAL BLOCK DIAGRAM
V
V
XTL_OUT XTL_IN SPDIF
REFOUT
REF
AD1981B
VOLTAGE
REFERENCE
G
MIC PREAMP
G
CODEC CORE
SPDIF
TX
MIC1
G
MIC2
PHONE_IN
CD_L
PCM L/R
ADC RATE
PLL
ID0
16-BIT
⌺-⌬ ADC
G
G
M
M
CD
DIFF AMP
CD_GND
CD_R
AUX_L
16-BIT
⌺-⌬ ADC
ID1
AUX_R
LINE_IN_L
LINE_IN_R
ADC
AND
RESET
SYNC
DAC
SLOT
LOGIC
16-BIT
G
G
M
M
⌺-⌬ ADC
16-BIT
⌺-⌬ ADC
BIT_CLK
SDATA_OUT
SDATA_IN
A
MONO_OUT
M
20-BIT
GA
M
M
⌺-⌬ DAC
EQ
HP
A
A
A
A
HP_OUT_L
LINE_OUT_L
LINE_OUT_R
HP_OUT_R
M
20-BIT
⌺-⌬ DAC
GA
GA
M
GA
M
EQ
PCM FRONT
DAC RATE
GA
M
GA
M
G = GAIN
MZ
GA
M
GA
M
A = ATTENUATION
M = MUTE
Z = HIGH Z
GA
M
GA
M
AC '97
MZ
CONTROL
REGISTERS
M
HP
M
ANALOG MIXING
CONTROL LOGIC
EAPD
M
JS0
JS1
EAPD
REV. B
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