REV. B

AD1981B

–8–

PIN FUNCTION DESCRIPTIONS

Pin No.

Mnemonic

I/O

Function

DIGITAL I/O

2

XTL_IN

I

Crystal Input (24.576 MHz) or External Clock Input.

3

XTL_OUT

O

Crystal Output.

5SDATA_OUT

I

AC-Link Serial Data Output, AD1981B Data Input Stream.

6

BIT_CLK

O/I

AC-Link Bit Clock Output (12.288 MHz) or Bit Clock Input if Secondary Mode

Selected.

8SDATA_IN

O

AC-Link Serial Data Input, AD1981B Data Output Stream.

10

SYNC

I

AC-Link Frame Sync.

11

RESET

I

AC-Link Reset, AD1981B Master Hardware Reset.

48

SPDIF

O

S/PDIF Output.

CHIP SELECTS (These pins can also be used to select an external clock. See Table IX.)

45

ID0

I

Chip Select Input 0 (Active Low). This pin can also be used as the chain input from

a secondary codec.

46

ID1

I

Chip Select Input 1 (Active Low).

JACK SENSE AND EAPD

17

JS0

I

Jack Sense 0 Input.

16

JS1

I

Jack Sense 1 Input.

47

EAPD

O

External Amp Power-Down Control.

ANALOG I/O

13

PHONE_IN

I

Phone Input. Mono input from telephony subsystem speaker phone or handset.

14

AUX_L

I

Auxiliary Input Left Channel.

15

AUX_R

I

Auxiliary Input Right Channel.

18

CD_L

I

CD Audio Left Channel.

19

CD_GND_REF

I

CD Audio Analog Ground Reference for Differential CD Input.

20

CD_ R

I

CD Audio Right Channel.

21

MIC1

I

Microphone 1 Input (Mono) or Left Channel when 2-Channel Mode

Selected (Stereo MIC).

22

MIC2

I

Microphone 2 Input (Mono) or Right Channel when 2-Channel Mode

Selected (Stereo MIC).

23

LINE_IN_L

I

Line In Left Channel.

24

LINE_IN_R

I

Line In Right Channel.

35

LINE_OUT_L

O

Line Out (Front) Left Channel.

36

LINE_OUT_R

O

Line Out (Front) Right Channel.

37

MONO_OUT

O

Monaural Output to Telephony Subsystem Speakerphone.

39

HP_OUT_L

O

Headphone Left Channel Output.

41

HP_OUT_R

O

Headphone Right Channel Output.

FILTER/REFERENCE (These signals are connected to resistors, capacitors, or specific voltages.)

27

O

Voltage Reference Filter.

28

O

Voltage Reference Output 5 mA Drive (Intended for MIC Bias and Power Amp Bias).

29

AFILT1

O

Antialiasing Filter Capacitor—ADC Right Channel.

30

AFILT2

O

Antialiasing Filter Capacitor—ADC Left Channel.

31

AFILT3

O

Antialiasing Filter Capacitor—Mixer ADC Right Channel.

32

AFILT4

O

Antialiasing Filter Capacitor—Mixer ADC Left Channel.

POWER AND GROUND SIGNALS

Digital GND.

Digital GND.

25

26

Analog GND.

38

40

Analog GND.

43

44

Analog GND.

34

33

Analog GND.

NO CONNECTS

12

NC

No Connect.

42

NC

No Connect.