Cirrus Logic CS4297A User Manual

Preliminary Product Information

This document contains information for a new product. Cirrus Logic reserves the right to modify this product without notice.

http://www.cirrus.com

CrystalClear® SoundFusion™ Audio Codec ‘97

CS4297A

March '06

DS318PP6

Preliminary Product Information

This document contains information for a new product. Cirrus Logic reserves the right to modify this product without notice.

http://www.cirrus.com

CrystalClear® SoundFusion™ Audio Codec ‘97

CS4297A

March '06

DS318PP6

CrystalClear SoundFusion™ Audio Codec ’97

Features

l AC ’97 2.1 Compatible

l Industry Leading Mixed Signal Technology

CS4297A

l Meets or Exceeds the Microsoft

Audio Performance Requirements

l S/PDIF Digital Audio Output l CrystalClear



3D Stereo Enhancement



PC 99

l 20-bit Stereo Digital-to-Analog Converters

l 18-bit Stereo Analog-to-Digital Converters

l Four Analog Line-level Stereo Inputs for

LINE_IN, CD, VIDEO, and AUX

l Two Analog Line-level Mono Inputs for

Modem and Internal PC Beep

l Dual Stereo Line-level Outputs for

LINE_OUT and ALT_LINE_OUT

l Dual Microphone Inputs

l High Quality Pseudo-Differential CD Input

l Extensive Power Management Support

AC-LINK AND AC’97

REGISTERS

PWR

MGT

SYNC

BIT_CLK

SDATA_OUT

SDATA_IN

RESET#

AC-

LINK

AC’97

REGISTERS

S/PDIF

PCM_DATA

GAIN / MUTE CONTROLS

MIXER / MUX SELECTS

PCM_DATA

Description

The CS4297A is an AC ’97 2.1 compatible stereo audio codec designed for PC multimedia systems. Using the industry leading CrystalClear signal technology, the CS4297A enables the design of PC 99-compliant desktop, portable, and entertainment PCs.

Coupling the CS4297A with a PCI audio accelerator or core logic supporting the AC ’97 interface, implements a cost effective, superior quality, audio solution. The CS4297A surpasses PC 99 and AC ’97 2.1 audio quality standards.

ORDERING INFO

CS4297A-KQZ lead-free 48-pin TQFP 9x9x1.4 mm CS4297A-JQZ lead-free 48-pin TQFP 9x9x1.4 mm

ANALOG INPUT MUX

AND OUTPUT MIXER

ADC

DAC

INPUT

MUX

OUTPUT

MIXER

18 bits

20 bits



delta-sigma and mixed

LINE CD AUX VIDEO

MIC1

MIC2

PHONE

PC_BEEP

LINE_OUT ALT_LINE_OUT MONO_OUT

Preliminary Product Information

P.O. Box 17847, Austin, Texas 78760 (512) 445 7222 FAX: (512) 445 7581 http://www.cirrus.com

This document contains information for a new product. Cirrus Logic reserves the right to modify this product without notice.

MAR ‘06

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TABLE OF CONTENTS

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1. CHARACTERISTICS AND SPECIFICATIONS .................................................................5

Analog Characteristics ........................................................................................................5

Mixer Characteristics ..........................................................................................................6

Absolute Maximum Ratings ................................................................................................6

Recommended Operating Conditions.................................................................................6

Digital Characteristics .........................................................................................................6

AC ’97 Serial Port Timing....................................................................................................7

2. GENERAL DESCRIPTION ...............................................................................................10

2.1 AC-Link ....................................................................................................................10

2.2 Control registers ......................................................................................................10

2.3 Output Mixer .............................................................................................................11

2.4 Input Mux .................................................................................................................11

2.5 Volume Control ........................................................................................................11

3. AC LINK FRAME DEFINITION .........................................................................................13

3.1 AC-Link Serial Data Output Frame ..........................................................................14

3.1.1 Serial Data Output Slot Tags (Slot 0) ...........................................................14

3.1.2 Command Address Port (Slot 1) ..................................................................15

3.1.3 Command Data Port (Slot 2) ........................................................................15

3.1.4 PCM Playback Data (Slots 3-10) .................................................................15

3.2 AC-Link Audio Input Frame ......................................................................................16

3.2.5 Serial Data Input Slot Tag Bits (Slot 0) .......................................................16

3.2.6 Status Address Port (Slot 1) .........................................................................16

3.2.7 Status Data Port (Slot 2) ..............................................................................17

3.2.8 PCM Capture Data (Slot 3-10) .....................................................................17

3.3 AC-Link Protocol Violation - Loss of SYNC ..............................................................18

4. REGISTER INTERFACE ..................................................................................................19

4.3 Reset Register (Index 00h) ......................................................................................20

4.4 Master Volume Register (Index 02h) .......................................................................20

4.5 Alternate Volume Register (Index 04h) ....................................................................21

4.6 Mono Volume Register (Index 06h) .........................................................................21

4.7 PC_BEEP Volume Register (Index 0Ah) .................................................................22

4.8 Phone Volume Register (Index 0Ch) ........................................................................22

4.9 Microphone Volume Register (Index 0Eh) ................................................................23

CS4297A

Contacting Cirrus Logic Support

For a complete listing of Direct Sales, Distributor, and Sales Representative contacts, visit the Cirrus Logic web site at:

http://www.cirrus.com/corporate/contacts/sales.cfm

Microsoft is a registered trademark of Microsoft Corporation in the United States and/or other countries. Intel is a registered trademark of Intel Corporation. Crystal Clear and Sound Fusion are trademarks of Cirrus Logic.

Preliminary product information describes products which are in production, but for which full characterization data is not yet available. Advance product information describes products which are in development and subject to development changes. Cirrus Logic, Inc. has made best efforts to ensure that the information contained in this document is accurate and reliable. However, the information is subject to change without notice and is provided “AS IS” without warranty of any kind (express or implied). No responsibility is assumed by Cirrus Logic, Inc. for the use of this information, nor for infringements of patents or other rights of third parties. This document is the property of Cirrus Logic, Inc. and implies no license under patents, copyrights, trademarks, or trade secrets. No part of this publication may be copied, reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photographic, or otherwise) without the prior written consent of Cirrus Logic, Inc. Items from any Cirrus Logic website or disk may be printed for use by the user. However, no part of the printout or electronic files may be copied, reproduced, stored in a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photographic, or otherwise) without the prior written consent of Cirrus Logic, Inc.Furthermore, no part of this publication may be used as a basis for manufacture or sale of any items without the prior written consent of Cirrus Logic, Inc. The names of products of Cirrus Logic, Inc. or other vendors and suppliers appearing in this document may be trademarks or service marks of their respective owners which may be registered in some jurisdictions. A list of Cirrus Logic, Inc. trademarks and service marks can be found at http://www.cirrus.com.

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4.10 Stereo Analog Mixer Input Gain Registers (Index 10h - 18h) ................................. 24

4.11 Input Mux Select Register (Index 1Ah) ................................................................... 25

4.12 Record Gain Register (Index 1Ch) ......................................................................... 25

4.13 General Purpose Register (Index 20h) ................................................................... 26

4.14 3D Control Register (Index 22h) .............................................................................26

4.15 Powerdown Control/Status Register (Index 26h) ................................................... 27

4.16 Extended Audio ID Register (Index 28h) ................................................................ 28

4.17 PCM Front DAC Rate Register (Index 2Ch) ........................................................ 28

4.18 PCM L/R ADC Rate Register (Index 32h) .............................................................. 28

4.19 AC Mode Control Register (Index 5Eh) .................................................................. 29

4.20 Misc. Crystal Control Register (Index 60h) ............................................................. 29

4.21 S/PDIF Control Register (Index 68h) ..................................................................... 30

4.22 Vendor ID1 Register (Index 7Ch) ........................................................................... 31

4.23 Vendor ID2 Register (Index 7Eh) ........................................................................... 31

5. POWER MANAGEMENT ................................................................................................. 32

5.1 AC ’97 Reset Modes ................................................................................................ 32

5.1.1 Cold AC ‘97 Reset ....................................................................................... 32

5.1.2 Warm AC ’97 Reset ..................................................................................... 32

5.1.3 Register AC ’97 Reset ................................................................................. 32

5.2 Powerdown Controls ................................................................................................33

6. ANALOG HARDWARE DESCRIPTION ......................................................................... 35

6.1 Analog Inputs ........................................................................................................... 35

6.1.4 Line-Level Inputs ........................................................................................35

6.1.5 CD Input .....................................................................................................35

6.1.6 Microphone Inputs ...................................................................................... 36

6.1.7 PC Beep Input ............................................................................................36

6.1.8 Phone Input ................................................................................................37

6.2 Analog Outputs ........................................................................................................ 37

6.2.9 Stereo Outputs ...........................................................................................37

6.2.10 Mono Output .............................................................................................37

6.3 Miscellaneous Analog Signals .................................................................................38

6.4 Power Supplies ........................................................................................................ 38

6.5 Reference Design .................................................................................................... 38

7. SONY/PHILIPS DIGITAL INTERFACE (S/PDIF) ............................................................ 39

8. GROUNDING AND LAYOUT .......................................................................................... 39

9. PIN DESCRIPTIONS 41

10. PARAMETER AND TERM DEFINITIONS ....................................................................46

11. REFERENCE DESIGN ................................................................................................. 48

12. REFERENCES .............................................................................................................. 49

13. PACKAGE DIMENSIONS ............................................................................................. 50

LIST OF FIGURES

Figure 1. Power Up Timing .......................................................................................................8

Figure 2. Codec Ready from Startup or Fault Condition ........................................................... 8

Figure 3. Clocks ........................................................................................................................ 8

Figure 4. Data Setup and Hold.................................................................................................. 9

Figure 5. PR4 Powerdown and Warm Reset ............................................................................ 9

Figure 6. Test Mode .................................................................................................................. 9

Figure 7. AC-link Connections ................................................................................................10

Figure 8. Mixer Diagram.......................................................................................................... 12

Figure 9. AC-link Input and Output Framing ........................................................................... 13

Figure 10. Line Input (Replicate for Video and Aux) ...............................................................35

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Figure 11. Differential 2 VRMS CD Input ................................................................................35

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Figure 12. Differential 1 VRMS CD Input ................................................................................35

Figure 13. Microphone Input ...................................................................................................36

Figure 14. Microphone Pre-amplifier .......................................................................................36

Figure 15. PC_BEEP Input......................................................................................................36

Figure 16. Modem Connection ................................................................................................37

Figure 17. Alternate Line Output as Headphone Output .........................................................37

Figure 18. Stereo Output .........................................................................................................37

Figure 19. Voltage Regulator ..................................................................................................38

Figure 20. S/PDIF Output ........................................................................................................39

Figure 21. Conceptual Layout for the CS4297A......................................................................40

Figure 22. Pin Locations for the CS4297A ..............................................................................41

Figure 23. CS4297A Reference Design ..................................................................................48

LIST OF TABLES

Table 1. Mixer Registers .........................................................................................................19

Table 2. Analog Mixer Output Attenuation ..............................................................................21

Table 3. Microphone Input Gain Values ..................................................................................23

Table 4. Analog Mixer Input Gain Values................................................................................24

Table 5. Stereo Volume Register Index ..................................................................................24

Table 6. Input Mux Selection...................................................................................................25

Table 7. Slot Mapping ............................................................................................................29

Table 8. Device ID with Corresponding Part Number .............................................................31

Table 9. Revision Values.........................................................................................................31

Table 10. Powerdown PR Bit Functions..................................................................................33

Table 11. Powerdown PR Function Matrix ..............................................................................34

Table 12. Power Consumption by Powerdown Mode .............................................................34

CS4297A

1. CHARACTERISTICS AND SPECIFICATIONS

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ANALOG CHARACTERISTICS Standard test conditions unless otherwise noted: T

AVdd = 5.0 V ±5%, DVdd = 3.3 V ±5%; 1 kHz Input Sine wave; Sample Frequency, Fs = 48 kHz; Z 1000 pF load, C

= 18 pF load (Note 1); Measurement bandwidth is 20 Hz - 20 kHz, 18-bit linear coding for ADC

ambient

=100 kΩ/

= 25° C,

functions, 20-bit linear coding for DAC functions; Mixer registers set for unity gain.

CS4297A-KQZ CS4297A-JQZ

Parameter

(Note 2)

Symbol Path

(Note 3)

UnitMin Typ Max Min Typ Max

Full Scale Input Voltage

Line Inputs Mic Inputs Mic Inputs (20 dB internal gain)

A-D A-D A-D

0.91

0.091

1.00

0.10

0.91

0.091

1.00

0.10

V V

RMS

Full Scale Output Voltage Line,Alternate Line, and Mono Outputs D-A 0.91 1.0 1.13 0.91 1.0 1.13 V

Frequency Response (Note 4) Analog Ac = ± 0.25 dB DAC Ac = ± 0.25 dB ADC Ac = ± 0.25 dB

Dynamic Range Stereo Analog inputs to LINE_OUT Mono Analog inputs to LINE_OUT DAC Dynamic Range ADC Dynamic Range

DAC SNR (-20 dB FS input w/ CCIR-RMS filter on output)

Total Harmonic Distortion + Noise

SNR

THD+N

20,000

90 85 87 85

20,000 20,000

A-A D-A A-D

A-A A-A D-A A-D

20 20 20

90 85 85 85

95 90 90 90

20,000 20,000 20,000

20 20 20

D-A-70---- dB

RMS

Hz Hz Hz

dB FS A dB FS A dB FS A dB FS A

(-3 dB FS input signal): Line/Alternate Line Output DAC ADC (all inputs except phone/mic) ADC (phone/mic)

A-A D-A A-D A-D

-74

-90

-91

-88

-84

-80

-74

dB FS dB FS dB FS dB FS

Power Supply Rejection Ratio (1 kHz, 0.5 V

w/ 5 V DC offset)(Note 4) 40 60 - - 40 - dB

RMS

Interchannel Isolation 70 88 - - 88 - dB Spurious Tone (Note 4) - -100 - - -100 - dB FS Input Impedance (Note 4) 10 - - 10 - - kΩ External Load Impedance 10 - - 10 - - kΩ Output Impedance (Note 4) - 730 - - 730 - Ω Input Capacitance (Note 4) - 5 - - 5 - pF Vrefout 2.0 2.28 2.5 2.0 2.28 2.5 V

Notes: 1. Z

refers to the analog output pin loading and CDL refers to the digital output pin loading.

2. Parameter definitions are given in the Section 10, Parameter and Term Definitions.

3. Path refers to the signal path used to generate this data. These paths are defined in the Section 10, Parameter and Term Definitions.

4. This specification is guaranteed by silicon characterization, it is not production tested.

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MIXER CHARACTERISTICS (for CS4297A-KQZ only)

Parameter Min Typ Max Unit

Mixer Gain Range Span Line In, Aux, CD, Video, Mic1, Mic2, Phone, PC Beep Mono Out, Alternate Line Out Line Out

Step Size All volume controls except PC Beep PC Beep

46.5

94.5

1.5

3.0

dB dB dB

dB dB

ABSOLUTE MAXIMUM RATINGS (AVss1 = AVss2 = DVss1 = DVss2 = 0 V)

Parameter Min Typ Max Unit

Power Supplies +3.3 V Digital

+5 V Digital

Analog Total Power Dissipation (Supplies, Inputs, Outputs) - - 1.25 W Input Current per Pin (Except Supply Pins) -10 - 10 mA Output Current per Pin (Except Supply Pins) -15 - 15 mA Analog Input voltage -0.3 - AVdd+

Digital Input voltage -0.3 - DVdd +

Ambient Temperature (Power Applied) -55 - 110 °C Storage Temperature -65 - 150 °C

-0.3

6.0

0.3

V V V

RECOMMENDED OPERATING CONDITIONS (AVss1 = AVss2 = DVss1 = DVss2 = 0 V)

Parameter Symbol Min Typ Max Unit

Power Supplies +3.3 V Digital

+5 V Digital

Analog

Operating Ambient Temperature 0 - 70 °C

DVdd1, DVdd2 DVdd1, DVdd2

AVdd1, AVdd2

3.135

4.75

3.3 5 5

3.465

5.25

V V V

DIGITAL CHARACTERISTICS (AVss = DVss = 0 V)

Parameter Symbol Min Typ Max Unit

Low level input voltage V High level input voltage V High level output voltage V Low level output voltage V Input Leakage Current (AC-link inputs) -10 - 10 µA Output Leakage Current (Tri-stated AC-link outputs) -10 - 10 µA Output buffer drive current

BIT_CLK, S/PDIF_OUT SDATA_IN, EAPD (Note 4)

- -0.8V

0.65 x DVdd - - V

0.90 x DVdd 0.99 x DVdd - V

- 0.03 0.10 x DVdd V

mA mA

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AC ’97 SERIAL PORT TIMING Standard test conditions unless otherwise noted: T

AVdd = 5.0 V, DVdd = 3.3 V; C

= 55 pF load.

ambient

= 25° C,

Parameter Symbol Min Typ Max Unit

RESET Timing

RESET# active low pulse width T RESET# inactive to BIT_CLK start-up delay T 1st SYNC active to CODEC READY set T Vdd stable to Reset inactive T

rst_low

rst2clk

sync2crd

vdd2rst#

1.0 - - µs

- 40.0 - µs

- 62.5 - µs

100 - - µs

Clocks

BIT_CLK frequency F BIT_CLK period T

clk_period

clk

- 12.288 - MHz

- 81.4 - ns BIT_CLK output jitter (depends on XTAL_IN source) - - 750 ps BIT_CLK high pulse width T BIT_CLK low pulse width T SYNC frequency F SYNC period T SYNC high pulse width T SYNC low pulse width T

sync_period

sync_high

sync_low

clk_high

clk_low

sync

36 40.7 45 ns 36 40.7 45 ns

-48-kHz

- 20.8 - µs

-1.3-µs

- 19.5 - µs

Data Setup and Hold

Output Propagation delay from rising edge of BIT_CLK T Input setup time from falling edge of BIT_CLK T Input hold time from falling edge of BIT_CLK T Input Signal rise time T Input Signal fall time T Output Signal rise time (Note 4) T Output Signal fall time (Note 4) T

isetup

ihold

irise

ifall

orise

ofall

81012ns

10 - - ns

0--ns 2-6ns 2-6ns 246ns 246ns

Misc. Timing Parameters

End of Slot 2 to BIT_CLK, SDATA_IN low (PR4) T SYNC pulse width (PR4) Warm Reset T SYNC inactive (PR4) to BIT_CLK start-up delay T Setup to trailing edge of RESET# (ATE test mode) (Note 4) T

s2_pdown

sync_pr4

sync2clk

setup2rst

Rising edge of RESET# to Hi-Z delay (Note 4) T

off

-.281.0µs

1.0 - - µs

162.8 285 - ns 15 - - ns

- - 25 ns

BIT_CLK

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RESET#

Vdd

BIT_CLK

SYNC

CODEC_READY

rst_low

vdd2rst#

Figure 1. Power Up Timing

sync2crd

rst2clk

BIT_CLK

orise

SYNC

irise

Figure 2. Codec Ready from Startup or Fault Condition

clk_highTclk_low

sync_high

Figure 3. Clocks

ifall

sync_period

clk_period

sync_low

ifall

BIT_CLK

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BIT_CLK

SDATA_IN

SDATA_OUT,

SYNC

Slot 1 Slot 2

isetup

Figure 4. Data Setup and Hold

ihold

CS4297A

SDATA_OUT

SDATA_IN

SYNC

Write to 0x20 Data PR4 Don’t Care

s2_pdown

Figure 5. PR4 Powerdown and Warm Reset

RESET#

setup2rst

SDATA_OUT,

SYNC

off

sync_pr4

sync2clk

SDATA_IN,

BIT_CLK

Figure 6. Test Mode

Hi-Z

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2. GENERAL DESCRIPTION

The CS4297A is a mixed-signal serial audio Codec compliant to the Intel® Audio Codec ‘97 Specifica- tion, revision 2.1 [1]. It is designed to be paired with a digital controller, typically located on the PCI bus or integrated within the system core logic chip set. The controller is responsible for all communications between the CS4297A and the remainder of the system. The CS4297A contains two distinct functional sections: digital and analog. The digital section includes the AC-link interface, S/PDIF interface, serial data port, and power management support. The analog section includes the analog input multiplexer (mux), stereo output mixer, mono output mixer, stereo Analog-to-Digital Converters (ADCs), stereo Digital-to-Analog Converters (DACs), and their associated volume controls.

2.1 AC-Link

All communication with the CS4297A is established with a 5-wire digital interface to the controller, as shown in Figure 7. This interface is called the AC-link. All clocking for the serial communication is synchronous to the BIT_CLK signal. BIT_CLK is generated by the primary audio codec and is used to clock the controller and any second-

ary audio codecs. Both input and output AC-link audio frames are organized as a sequence of 256 serial bits forming 13 groups referred to as ‘slots’. During each audio frame, data is passed bi-directionally between the CS4297A and the controller. The input frame is driven from the CS4297A on the SDATA_IN line. The output frame is driven from the controller on the SDATA_OUT line. The controller is also responsible for issuing reset commands via the RESET# signal. Following a Cold Reset, the CS4297A is responsible for notifying the controller that it is ready for operation after synchronizing its internal functions. The CS4297A AC-link signals must use the same digital supply voltage as the controller chip, either +5 V or +3.3 V. See Section 3, AC Link Frame Definition, for detailed AC-link information.

2.2 Control registers

The CS4297A contains a set of AC ’97 compliant control registers and a set of Cirrus Logic defined control registers. These registers control the basic functions and features of the CS4297A. Read accesses of the control registers by the AC ’97 controller are accomplished with the requested register index in Slot 1 of a SDATA_OUT frame. The following SDATA_IN frame will contain the read

Digital AC’97

Controller

Figure 7. AC-link Connections

SYNC

BIT_CLK

SDATA_OUT

SDATA_IN

RESET#

CODEC

CS4297A

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data in its Slot 2. Write operations are similar, with the register index in Slot 1 and the write data in Slot 2 of a SDATA_OUT frame. The function of each input and output frame is detailed in Section 3, AC Link Frame Definition. Individual register descriptions are found in Section 4, Register Inter- face.

2.3 Output Mixer

The CS4297A has two output mixers, illustrated in Figure 8. The stereo output mixer sums together the analog inputs to the CS4297A, including the PC_BEEP and PHONE signals, according to the settings in the volume control registers. The stereo output mix is sent to the LINE_OUT and ALT_LINE_OUT pins on the CS4297A. The mono output mixer generates a monophonic sum of the left and right channels from the stereo input mixer. The mono output mix is sent to the MONO_OUT output pin on the CS4297A.

2.4 Input Mux

The input multiplexer controls which analog input is sent to the ADCs. The output of the input mux is converted to stereo 18-bit digital PCM data and sent to the controller by means of the AC-link SDATA_IN signal.

2.5 Volume Control

The CS4297A volume registers control analog input levels to the input mixer and analog output levels, including the master volume level, and the alternate volume level. The PC_BEEP volume control uses 3 dB steps with a range of 0 dB to -45 dB attenuation. All other analog volume controls use

1.5 dB steps. The analog inputs have a mixing range of +12 dB signal gain to -34.5 dB signal attenuation. The analog output volume controls have from 0 dB to -94.5 dB attenuation for LINE_OUT and from 0 dB to -46.5 dB attenuation for ALT_LINE_OUT and MONO_OUT.

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PC_BEEP

PHONE

PCM_OUT

MIC1

MIC2

LINE

VIDEO

AUX

MIC

SELECT

MAIN D/A

CONVERTERS

DAC

BOOST

VOL

VOL VOL

VOL VOL VOL

MUTE

PC BEEP BYPASS

Σ Σ

INPUT MIXER

ANALOG STEREO

OUTPUT MIXER

STEREO TO

MONO MIXER

1/2

STEREO TO

MONO MIXER

1/2

BYPASS BUFFER

3D OUTPUT

MIXER

DAC DIRECT

MONO OUT

ADC

INPUT

MUX

MODE

SELECT

MASTER VOLUME

VOL VOL

ALT LINE VOLUME

MONO

VOLUME

VOL

MAIN ADC

GAIN

VOL

MUTE

OUTPUT BUFFER

MAIN A/D

CONVERTERS

ADCMUTE

LINE OUT

ALT LINE OUT

MONO OUT

PCM_IN

Figure 8. Mixer Diagram

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3. AC LINK FRAME DEFINITION

The AC-link is a bidirectional serial port with data organized into frames consisting of one 16-bit and twelve 20-bit time-division multiplexed slots. The first slot, called the tag slot, contains bits indicating if the CS4297A is ready to receive data (input frame) and which, if any, other slots contain valid data. Slots 1 through 12 contain audio or control/status data. Both the serial data output and input frames are defined from the controller perspective, not from the CS4297A perspective.

The controller synchronizes the beginning of a frame with the assertion of the SYNC signal.

Tag Phase Data Phase

Figure 9 shows the position of each bit location within the frame. The first bit position in a new serial data frame is F0 and the last bit position in the serial data frame is F255. When SYNC goes active (high) and is sampled active by the CS4297A (on the falling edge of BIT_CLK), both devices are synchronized to a new serial data frame. The data on the SDATA_OUT pin at this clock edge is the

final bit of the previous frame’s serial data. On the next rising edge of BIT_CLK, the first bit of Slot 0 is driven by the controller on the SDATA_OUT pin. On the next falling edge of BIT_CLK, the CS4297A latches this data in, as the first bit of the frame.

20.8 µs

(48 kHz)

SYNC

BIT_CLK

Bit Frame Position:

SDATA_OUT

Bit Frame Position:

SDATA_IN

12.288 MHz

81.4 ns

F0 F1 F2 F16F15F14F13F12

F255

Valid

Frame

F0 F1 F2 F16F15F14F13F12 F35 F56 F76F255

Codec Ready

Slot 1

Valid

Slot 1 Valid

GPIO

INT

Slot 2

Valid

Slot 2

Valid

F36 F57

Slot 12

Valid

Slot 12

Valid

Slot 0 Slot 1 Slot 2 Slot 3 Slot 4 Slots 5-12

Codec

ID1

R/W 0 WD15

ID0

0000

F35

F36

F56

D19 D18

F57

D19 D18 D19RD15

F76

D19

F96

D19

F96

D19

Figure 9. AC-link Input and Output Framing

F255

GPIO

INT

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3.1 AC-Link Serial Data Output Frame

In the serial data output frame, data is passed on the SDATA_OUT pin to the CS4297A from the AC ’97 controller. Figure 9 illustrates the serial port timing.

The PCM playback data being passed to the CS4297A is shifted out MSB first in the most significant bits of each slot. Any PCM data from the AC ’97 controller that is not 20 bits wide should be left justified in its corresponding slot and dithered or zero-padded in the unused bit positions.

Bits that are reserved should always be ‘cleared’ by the AC ’97 controller.

3.1.1 Serial Data Output Slot Tags (Slot 0)

Bit 1514131211109876543210

Val id

Slot 1

Frame

Valid Frame The Valid Frame bit determines if any of the following slots contain either valid playback data

Slot [1:2] Valid The Slot [1:2] Valid bits indicate the validity of data in their corresponding serial data output

Valid

Slot 2

Slot 3

Valid

for the CS4297A DACs or data for read/write operations. When ‘set’, at least one of the other AC-link slots contain valid data. If this bit is ‘clear’, the remainder of the frame is ignored.

slots. If a bit is ‘set’, the corresponding output slot contains valid data. If a bit is ‘cleared’, the corresponding slot will be ignored.

Slot 4

Valid

Slot 5

Valid

Slot 6

Valid

Slot 7

Valid

Slot 8

Valid

Slot 9

Valid

Slot 10

Valid

Reserved

Codec

ID1

Codec

ID0

Slot [3:10] Valid The Slot [3:10] Valid bits indicate Slot [3:10] contains valid playback data for the CS4297A. If a

Slot Valid bit is ‘set’, the named slot contains valid audio data. If the bit is ‘clear’, the slot will be ignored. The CS4297A supports alternate slot mapping as defined in the AC ’97 2.1 specification. For more information, see the AC Mode Control Register (Index 5Eh).

Codec ID[1:0] The Codec ID[1:0] bits display the Codec ID of the audio codec being accessed during the cur-

rent AC-link frame. Codec ID[1:0] = 00 indicates the primary codec is being accessed. Codec ID[1:0] = 01, 10, or 11 indicates one of three possible secondary codecs is being accessed. A non-zero value of one or more of the Codec ID bits indicates a valid Read or Write Address in Slot 1, and the Slot 1 R/W bit indicates presence or absence of valid Data in Slot 2.

CS4297A

DS318PP6 15

CS4297A

3.1.2 Command Address Port (Slot 1)

Bit 191817161514131211109876543210

R/W RI6RI5RI4RI3RI2RI1RI0000000000000

R/W Read/Write. When this bit is ‘set’, a read of the AC ’97 register specified by the register index

bits will occur in the AC ’97 2.1 audio codec. When the bit is ‘cleared’, a write will occur. For any read or write access to occur, the Frame Valid bit (F0) must be ‘set’ and the Codec ID[1:0] bits (F[14:15]) must match the Codec ID of the AC ’97 2.1 audio codec being accessed. Additionally, for a primary codec, the Slot 1 Valid bit (F1) must be ‘set’ for a read access and both the Slot 1 Valid bit (F1) and the Slot 2 Valid bit (F2) must be ‘set’ for a write access. For a secondary codec, both the Slot 1 Valid bit (F1) and the Slot 2 Valid bit (F2) must be ‘cleared’ for read and write accesses. See Figure 9 for bit frame positions.

RI[6:0] Register Index. The RI[6:0] bits contain the 7-bit register index to the AC ’97 registers in the

CS4297A. All registers are defined at word addressable boundaries. The RI0 bit must be ‘clear’ to access CS4297A registers.

3.1.3 Command Data Port (Slot 2)

Bit 191817161514131211109876543210

WD15 WD14 WD13 WD12 WD11 WD10 WD9 WD8 WD7 WD6 WD5 WD4 WD3 WD2 WD1 WD0 Reserved

WD[15:0] Write Data. The WD[15:0] bits contain the 16-bit value to be written to the register. If an access

is a read, this slot is ignored.

NOTE: For any write to an AC ’97 register, the write is defined to be an ‘atomic’ access. This means

that when the Slot 1 Valid bit in output Slot 0 is ‘set’, the Slot 2 Valid bit in output slot 0 should always be ‘set’ during the same audio frame. No write access may be split across 2 frames.

3.1.4 PCM Playback Data (Slots 3-10)

Bit 191817161514131211109876543210

PD19 PD18 PD17 PD16 PD15 PD14 PD13 PD12 PD11 PD10 PD9 PD8 PD7 PD6 PD5 PD4 PD3 PD2 PD1 PD0

PD[19:0] Playback Data. The PD[19:0] bits contain the 20-bit PCM playback (2’s complement) data for

the left and right DACs and/or the S/PDIF transmitter. Table 7 on page 29 lists a cross reference for each function and its respective slot. The mapping of a given slot to a DAC is determined by the state of the ID[1:0] bits in the Extended Audio ID Register (Index 28h) and by the SM[1:0] and AMAP bits in the AC Mode Control Register (Index 5Eh).

CS4297A

16 DS318PP6

CS4297A

3.2 AC-Link Audio Input Frame

In the serial data input frame, data is passed on the SDATA_IN pin from the CS4297A to the AC ’97 con- troller. The data format for the input frame is very similar to the output frame. Figure 9 on page 13 illustrates the serial port timing.

The PCM capture data from the CS4297A is shifted out MSB first in the most significant 18 bits of each slot. The least significant 2 bits in each slot will be ‘cleared’. If the host requests PCM data from the AC ’97 Controller that is less than 18 bits wide, the controller should dither and round or just round (but not truncate) to the desired bit depth.

Bits that are reserved or not implemented in the CS4297A will always be returned ‘cleared’.

3.2.1 Serial Data Input Slot Tag Bits (Slot 0)

Bit 1514131211109876543210

Codec Ready

Codec Ready The Codec Ready bit indicates the readiness of the CS4297A AC-link. Immediately after a

Slot 1

Valid

Slot 2

Valid

Slot 3

Valid

Cold Reset this bit will be ‘clear’. Once the CS4297A clocks and voltages are stable, this bit will be ‘set’. Until the Codec Ready bit is ‘set’, no AC-link transactions should be attempted by the controller. The Codec Ready bit does not indicate readiness of the DACs, ADCs, Vref, or any other analog function. Those must be checked in the Powerdown Control/Status Reg- ister (Index 26h) by the controller before any access is made to the mixer registers. Any accesses to the CS4297A while Codec Ready is ‘clear’ are ignored.

Slot 4

Valid

Slot 5

Valid

Slot 6

Valid

Slot 7

Valid

Slot 8

Valid

Slot 9

Valid

Slot 10

Valid

00000

Slot 1 Valid When ‘set’, the Slot 1 Valid bit indicates Slot 1 contains a valid read back address.

Slot 2 Valid When ‘set’, the Slot 2 Valid bit indicates Slot 2 contains valid register read data.

Slot [3:10] Valid When ‘set’, the Slot [3:10] Valid bits indicate Slot [3:10] contains valid capture data from the

CS4297A ADCs. Only if a Slot [3:10] Valid bit is ‘set’ will the corresponding input slot contain valid data.

3.2.2 Status Address Port (Slot 1)

Bit 1918171615141312111098 76 5 4 3210

0 RI6 RI5 RI4 RI3 RI2 RI1 RI0 0 0 0 0 0 0 0 0 0 Reserved

RI[6:0] Register Index. The RI[6:0] bits echo the AC ’97 register address when a register read has

been requested in the previous frame. The CS4297A will only echo the register index for a read access. Write accesses will not return valid data in Slot 1.

CS4297A

DS318PP6 17

CS4297A

3.2.3 Status Data Port (Slot 2)

Bit 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0

RD15 RD14 RD13 RD12 RD11 RD10 RD9 RD8 RD7 RD6 RD5 RD4 RD3 RD2 RD1 RD0 Reserved

RD[15:0] Read Data. The RD[15:0] bits contain the register data requested by the controller from the

previous read request. All read requests will return the read address in the input Slot 1 and the register data in the input Slot 2 on the following serial data frame.

3.2.4 PCM Capture Data (Slot 3-10)

Bit 191817161514131211109876543210

CD17 CD16 CD15 CD14 CD13 CD12 CD11 CD10 CD9 CD8 CD7 CD6 CD5 CD4 CD3 CD2 CD1 CD0 0 0

CD[17:0] Capture Data. The D[17:0] bits contain 18-bit PCM (2’s complement) capture data. The map-

ping of a given slot to an ADC is determined by the state of the ID[1:0] bits in the Extended

Audio ID Register (Index 28h) and the SM[1:0] and AMAP bits in the AC Mode Control Register (Index 5Eh). The definition of each slot can be found in Table 7 on page 29.

CS4297A

18 DS318PP6

CS4297A

3.3 AC-Link Protocol Violation - Loss of SYNC

The CS4297A is designed to handle SYNC protocol violations. The following are situations where the SYNC protocol has been violated:

• The SYNC signal is not sampled high for exact-

ly 16 BIT_CLK clock cycles at the start of an audio frame.

• The SYNC signal is not sampled high on the

256th BIT_CLK clock period after the previous SYNC assertion.

• The SYNC signal goes active high before the

256th BIT_CLK clock period after the previous SYNC assertion.

Upon loss of synchronization with the controller, the CS4297A will ‘clear’ the Codec Ready bit in the serial data input frame until two valid frames are detected. During this detection period, the CS4297A will ignore all register reads and writes and will discontinue the transmission of PCM capture data. In addition, if the LOSM bit in the Misc. Crystal Control Register (Index 60h) is ‘set’ (de- fault), the CS4297A will mute all analog outputs. If the LOSM bit is ‘clear’, the analog outputs will not be muted.

CS4297A

DS318PP6 19

CS4297A

4. REGISTER INTERFACE

Reg Register Name D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 Default

00h Reset 0 SE4 SE3 SE2 SE1 SE0 0 ID8 ID7 0 0 ID4 0 0 0 0 1990h

02h Master Volume Mute 0 ML5 ML4 ML3 ML2 ML1 ML0 0 0 MR5 MR4 MR3 MR2 MR1 MR0 8000h

04h Alternate Volume Mute 0 ML5

06h Mono Volume Mute 000000000MM5

0AhPC_BEEP Volume Mute0000000000PV3PV2PV1PV000000h

0Ch Phone Volume Mute 0000000000GN4GN3GN2GN1GN08008h

0EhMic Volume Mute00000000

10h Line In Volume Mute 0 0 GL4 GL3 GL2 GL1 GL0 0 0 0 GR4 GR3 GR2 GR1 GR0 8808h

12h CD Volume Mute 0 0 GL4 GL3 GL2 GL1 GL0 0 0 0 GR4 GR3 GR2 GR1 GR0 8808h

14h Video Volume Mute 0 0 GL4 GL3 GL2 GL1 GL0 0 0 0 GR4 GR3 GR2 GR1 GR0 8808h

16h Aux Volume Mute 0 0 GL4 GL3 GL2 GL1 GL0 0 0 0 GR4 GR3 GR2 GR1 GR0 8808h

18h PCM Out Volume Mute 0 0 GL4 GL3 GL2 GL1 GL0 0 0 0 GR4 GR3 GR2 GR1 GR0 8808h

1AhRecord Select 00000SL2SL1SL000000SR2SR1SR00000h

1Ch Record Gain Mute 0 0 0 GL3 GL2 GL1 GL0 0 0 0 0 GR3 GR2 GR1 GR0 8000h

20h General Purpose 0 0 3D 0 0 0 MIX MS

22h3D Control 0 00000000000S3S2S1S00000h

EAPD

26h Powerdown Ctrl/Stat

28h Extended Audio ID ID1 ID0 0000

2Ch PCM Front DAC Rate

32h PCM L/R ADC Rate

PR6 PR5 PR4 PR3 PR2 PR1 PR0 0 0 0 0 REF ANL DAC ADC 000Fh

SR15 SR14 SR13 SR12 SR11 SR10

Cirrus Logic Defined Registers:

5E AC Mode Control 0 00000 0

60 Misc. Crystal Control 0 0 0 0 Reserved 0 0 Reserved 0 Reserved

SPEN

68 S/PDIF Control

7Ch Vendor ID1(CR) F7 F6 F5 F4 F3 F4 F1 F0 S7 S6 S5 S4 S3 S2 S1 S0 4352h

7Eh Vendor ID2(Y-) T7 T6 T5 T4 T3 T2 T1 T0 0

Val 0 Fs L CC6 CC5 CC4 CC3 CC2 CC1 CC0

ML4 ML3 ML2 ML1 ML0 0 0 MR5 MR4 MR3 MR2 MR1 MR0 8000h

MM4 MM3 MM2 MM1 MM0 8000h

20dB

0 GN4 GN3 GN2 GN1 GN0 8008h

LPBK

0 0 0 0 0 0 0 0000h

AMAP

0 0 0 0 0 0 0 0 VRA 0201h

SR9 SR8 SR7 SR6 SR5 SR4 SR3 SR2 SR1 SR0 BB80h

DDM AMAP

0 SM1 SM0 0 0 0 0 0080h

LOSM

0023h

DID2 DID1 DID0

Emph Copy /Audio

REV2 REV1 REV0

Pro 0000h

5931h

Table 1. Mixer Registers

CS4297A

20 DS318PP6

CS4297A

4.1 Reset Register (Index 00h)

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

0SE4SE3SE2SE1SE00ID8ID700ID40000

SE[4:0] Crystal 3D Stereo Enhancement. SE[4:0] = 00110, indicating this feature is present.

ID8 18-bit ADC Resolution. The ID8 bit is ‘set’, indicating this feature is present.

ID7 20-bit DAC resolution. The ID7 bit is ‘set’, indicating this feature is present.

ID4 Headphone Output (Alt Line Out). The ID4 bit is ‘set’, indicating this feature is present.

Default 1990h. The data in this register is read-only data.

Any write to this register causes a Register Reset to the default state of the audio (Index 00h - 38h) and vendor spe- cific (Index 5Ah - 7Ah) registers. A read from this register returns configuration information about the CS4297A.

4.2 Master Volume Register (Index 02h)

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

Mute 0 ML5 ML4 ML3 ML2 ML1 ML0 0 0 MR5 MR4 MR3 MR2 MR1 MR0

Mute Master Mute. Setting this bit mutes the LINE_OUT_L/R output signals.

ML[5:0] Master Volume Left. These bits control the left master output volume. Each step corresponds

to 1.5 dB gain adjustment, with 00000 = 0 dB. The total range is 0 dB to -94.5 dB attenuation.

MR[5:0] Master Volume Right. These bits control the right master output volume. Each step corresponds

to 1.5 dB gain adjustment, with 00000 = 0 dB. The total range is 0 dB to -94.5 dB attenuation.

Default 8000h. This value corresponds to 0 dB attenuation and Mute ‘set’.

CS4297A

DS318PP6 21

CS4297A

4.3 Alternate Volume Register (Index 04h)

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

Mute 0 ML5

Mute Alternate Mute. Setting this bit mutes the ALT_LINE_OUT_L/R output signals.

ML[4:0] Alternate Volume Left. These bits control the left alternate output volume. Each step corre-

ML4 ML3 ML2 ML1 ML0 0 0 MR5 MR4MR3MR2MR1MR0

sponds to 1.5 dB gain adjustment, with 00000 = 0 dB. The total range is 0 dB to -46.5 dB attenuation. See Table 2 for further attenuation levels.

ML5

MR[4:0] Alternate Volume Right. These bits control the right alternate output volume. Each step corre-

MR5

Default 8000h. This value corresponds to 0 dB attenuation and Mute ‘set’.

Alternate Volume Left Max Attenuation. Setting ML5 sets the left channel attenuation to

-46.5 dB by forcing ML[4:0] to a ‘1’ state. ML[5:0] will read back 011111 when ML5 ‘set’. Table 2 summarizes this behavior.

sponds to 1.5 dB gain adjustment, with 00000 = 0 dB. The total range is 0 dB to -46.5 dB attenuation. See Table 2 for further attenuation levels.

Alternate Volume Right Max Attenuation. Setting MR5 sets the right channel attenuation to

-46.5 dB by forcing MR[4:0] to a ‘1’ state. MR[5:0] will read back 011111 when MR5 ‘set’. Table 2 summarizes this behavior.

Mx[5:0]

Write

000000 000000 0 dB

000001 000001 -1.5 dB

……...

011111 011111 -46 . 5 d B

100000 011111 -46. 5 d B

... ... ...

111111 011111 - 46 .5 d B

Mx[5:0]

Read

Gain

Level

has been

Table 2. Analog Mixer Output Attenuation

4.4 Mono Volume Register (Index 06h)

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

Mute000000000MM5

Mute Mono Mute. Setting this bit mutes the MONO_OUT signal.

MM[5:0] Mono Volume. These bits control the mono output volume. Each step corresponds to 1.5 dB

gain adjustment, with a total available range from 0 dB to -46.5 dB attenuation. See Table 2 for further attenuation levels.

MM5

Default 8000h. This value corresponds to 0 dB attenuation and Mute ‘set’.

Mono Volume Max Attenuation. Setting the MM5 bit sets the mono attenuation to -46.5 dB by forcing MM[4:0] to a ‘1’ state. MM[5:0] will read back 011111 when MM5 summarizes this behavior.

MM4 MM3 MM2 MM1 MM0

has been ‘set’. Table 2

CS4297A

22 DS318PP6

CS4297A

4.5 PC_BEEP Volume Register (Index 0Ah)

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

Mute 0 0 0 0 0 0 0 0 0 0 PV3 PV2 PV1 PV0 0

Mute PC_BEEP Mute. Setting this bit mutes the PC_BEEP input signal.

PV[3:0] PC_BEEP Volume Control. The PV[3:0] bits are used to control the gain levels of the PC_BEEP

input source to the Input Mixer. Each step corresponds to 3 dB gain adjustment, with 0000 = 0 dB. The total range is 0 dB to -45 dB attenuation.

Default 0000h. This value corresponds to 0 dB attenuation and Mute ‘clear’.

This register has no effect on the PC_BEEP volume during RESET#.

4.6 Phone Volume Register (Index 0Ch)

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

Mute0000000000GN4GN3GN2GN1GN0

Mute Phone Mute. Setting this bit mutes the Phone input signal.

GN[4:0] Phone Volume Control. The GN[4:0] bits are used to control the gain levels of the Phone input

source to the Input Mixer. Each step corresponds to 1.5 dB gain adjustment, with 01000 = 0 dB. The total range is +12 dB to -34.5 dB gain. See Table 4 on page 24 for further details.

Default 8008h. This value corresponds to 0 dB gain and Mute ‘set’.

CS4297A

DS318PP6 23

CS4297A

4.7 Microphone Volume Register (Index 0Eh)

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

Mute0000000020dB0GN4GN3GN2GN1GN0

Mute Microphone Mute. Setting this bit mutes the MIC1 or MIC2 signal. The selection of the MIC1 or

MIC2 input pin is controlled by the MS bit in the General Purpose Register (Index 20h).

GN[4:0] Microphone Volume Control. The GN[4:0] bits are used to control the gain level of the Micro-

phone input source to the Input Mixer. Each step corresponds to 1.5 dB gain adjustment, with 01000 = 0 dB. The total range is +12 dB to -34.5 dB gain. See Table 3 for further details.

20dB Microphone 20 dB Boost. When ‘set’, the 20dB bit enables the +20 dB microphone boost block.

This bit allows for variable boost of 0 dB or +20 dB. Table 3 summarizes this behavior.

Default 8008h. This value corresponds to 0 dB gain and Mute ‘set’.

GN[4:0]

00000 +12.0 dB +32.0 dB

00001 +10.5 dB +30.5 dB

……...

00111 +1.5 dB +21.5 dB

01000 0.0 dB +20.0 dB

01001 -1.5 dB +18.5 dB

……...

11111 -34.5 dB -14 . 5 d B

Table 3. Microphone Input Gain Values

Gain Level

20dB = 0 20dB = 1

CS4297A

24 DS318PP6

CS4297A

4.8 Stereo Analog Mixer Input Gain Registers (Index 10h - 18h)

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

Mute 0 0 GL4 GL3 GL2 GL1 GL0 0 0 0 GR4 GR3 GR2 GR1 GR0

Mute Stereo Input Mute. Setting this bit mutes the respective input signal, both right and left inputs.

GL[4:0] Left Volume Control. The GL[4:0] bits are used to control the gain level of the left analog input

source to the Input Mixer. Each step corresponds to 1.5 dB gain adjustment, with 01000 = 0 dB. The total range is +12 dB to -34.5 dB gain. See Table 4 for further details.

GR[4:0] Right Volume Control. The GR[4:0] bits are used to control the gain level of the right analog in-

put source to the Input Mixer. Each step corresponds to 1.5 dB gain adjustment, with 01000 = 0 dB. The total range is +12 dB to -34.5 dB gain. See Table 4 for further details.

Default 8808h. This value corresponds to 0 dB gain and Mute ‘set’.

The Stereo Analog Mixer Input Gain Registers are listed in Table 5.

Gx[4:0] Gain Level

00000 +12.0 dB

00001 +10.5 dB

……

00111 +1.5 dB

01000 0.0 dB

01001 -1.5 dB

……

11111 -3 4. 5 dB

Table 4. Analog Mixer Input Gain Values

10h Line In Volume

12h CD Volume

14h Video Volume

16h Aux Volume

18h PCM Out Volume

Table 5. Stereo Volume Register Index

CS4297A

DS318PP6 25

CS4297A

4.9 Input Mux Select Register (Index 1Ah)

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

00000SL2SL1SL000000SR2SR1SR0

SL[2:0] Left Channel Source. The SL[2:0] bits select the left channel source to pass to the ADCs for

recording. See Table 6 for possible values.

SR[2:0] Right Channel Source. The SR[2:0] bits select the right channel source to pass to the ADCs for

recording. See Table 6 for possible values.

Default 0000h. This value selects the Mic input for both channels.

Sx[2:0] Record Source

000 Mic

001 CD Input

010 Video Input

011 Aux Input

100 Line Input

101 Stereo Mix

110 Mono Mix

111 Phone Input

Table 6. Input Mux Selection

4.10 Record Gain Register (Index 1Ch)

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

Mute 0 0 0 GL3 GL2 GL1 GL0 0 0 0 0 GR3 GR2 GR1 GR0

Mute Record Gain Mute. Setting this bit mutes the input to the L/R ADCs.

GL[3:0] Left ADC Gain. The GL[3:0] bits control the input gain on the left channel of the analog source,

applied after the input mux and before the ADCs. Each step corresponds to 1.5 dB gain adjustment, with 0000 = 0 dB. The total range is 0 dB to +22.5 dB gain.

GR[3:0] Right ADC Gain. The GR[3:0] bits control the input gain on the right channel of the analog

source, applied after the input mux and before the ADCs. Each step corresponds to 1.5 dB gain adjustment, with 0000 = 0 dB. The total range is 0 dB to +22.5 dB gain.

Default 8000h. This value corresponds to 0 dB gain and Mute ‘set’.

CS4297A

26 DS318PP6

CS4297A

4.11 General Purpose Register (Index 20h)

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

003D000MIXMSLPBK0000000

3D 3D Enable. When ‘set’, the 3D bit enables the CrystalClearTM 3D stereo enhancement. This

function is not available in DAC Direct Mode (DDM).

MIX Mono Output Select. The MIX bit selects the source for the Mono Out output. When ‘set’, the

microphone input is selected. When ‘clear’, the stereo-to-mono mixer is selected.

MS Microphone Select. The MS bit determines which of the two Mic inputs are passed to the mixer.

When ‘set’, the MIC2 input is selected. When ‘clear’, the MIC1 input is selected.

LPBK Loopback Enable. When ‘set’, the LPBK bit enables the ADC/DAC Loopback Mode. This bit

routes the output of the ADCs to the input of the DACs without involving the AC-link.

Default 0000h

4.12 3D Control Register (Index 22h)

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

000000000000S3S2S1S0

S[3:0] Spacial Enhancement Depth. These bits control the amount of “space” added to the output ste-

reo signal. When S[3:0] = 0000, the minimum amount of spatial enhancement is added. When S[3:0] = 1111, the maximum amount of spatial enhancement is added. The 3D function is enabled and disabled by the 3D bit in the General Purpose Register (Index 20h).

Default 0000h. This value corresponds to minimum spatial enhancement added to the output signal.

CS4297A

DS318PP6 27

CS4297A

4.13 Powerdown Control/Status Register (Index 26h)

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

EAPD PR6 PR5 PR4 PR3 PR2 PR1 PR0 0 0 0 0 REF ANL DAC ADC

EAPD External Amplifier Power Down. The EAPD pin follows this bit and is generally used to power

down external amplifiers.

PR6 Alternate Line Out Powerdown. When ‘set’, the alternate line out buffer is powered down.

PR5 Internal Clock Disable. When ‘set’, this bit completely powers down both the analog and digital

sections of the CS4297A. The only way to recover from setting this bit is through a Cold Reset (driving the RESET# signal active).

PR4 AC-link Powerdown. When ‘set’, the AC link is powered down (BIT_CLK off). The AC-link can

be restarted through a Warm Reset using the SYNC signal, or a Cold Reset using the RESET# signal (primary audio codec only).

PR3 Analog Mixer Powerdown (Vref off). When ‘set’, the analog mixer and voltage reference are

powered down. When clearing this bit, the ANL, ADC, and DAC bits should be checked before writing any mixer registers.

PR2 Analog Mixer Powerdown (Vref on). When ‘set’, the analog mixer is powered down (the voltage

reference is still active). When clearing this bit, the ANL bit should be checked before writing any mixer registers.

PR1 Front DACs Powerdown. When ‘set’, the DACs are powered down. When clearing this bit, the

DAC bit should be checked before sending any data to the DACs.

PR0 L/R ADCs and Input Mux Powerdown. When ‘set’, the ADCs and the ADC input muxes are pow-

ered down. When clearing this bit, no valid data will be sent down the AC link until the ADC bit goes high.

REF Voltage Reference Ready Status. When ‘set’, indicates the voltage reference is at a nominal

level.

ANL Analog Ready Status. When ‘set’, the analog output mixer, input multiplexer, and volume con-

trols are ready. When clear, no volume control registers should be written.

DAC Front DAC Ready Status. When ‘set’, the DACs are ready to receive data across the AC link.

When clear, the DACs will not accept any valid data.

ADC L/R ADC Ready Status. When ‘set’, the ADCs are ready to send data across the AC link. When

clear, no data will be sent to the Controller.

Default 0000h. This value indicates all blocks are powered on. The lower four bits will change as the

CS4297A finishes an initialization and calibration sequence.

The PR[6:0] and the EAPD bits are powerdown control for different sections of the CS4297A as well as external amplifiers. The REF, ANL, DAC, and ADC bits are read-only status bits which, when ‘set’, indicate that a particular section of the CS4297A is ready. After the controller receives the Codec Ready bit in input Slot 0, these status bits must be checked before writing to any mixer registers. See Section 5, Power Management, for more information on the powerdown functions.

CS4297A

28 DS318PP6

CS4297A

4.14 Extended Audio ID Register (Index 28h)

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

ID1ID00000AMAP00000000VRA

ID[1:0] Codec Configuration ID. When ID[1:0] = 00, the CS4297A is the primary audio codec. When

ID[1:0] = 01, 10, or 11, the CS4297A is a secondary audio codec. The state of the ID[1:0] bits is determined at power-up from the ID[1:0]# pins.

AMAP Audio Slot Mapping. The AMAP bit indicates whether the optional AC ’97 2.1 compliant AC-link

slot to audio DAC mapping is supported. This bit is a shadow of the AMAP bit in the AC Mode Control Register (Index 5Eh). The PCM playback and capture slots are mapped according to Table 7 on page 29.

VRA Variable Rate PCM Audio. The VRA bit indicates whether variable rate PCM audio is supported.

This bit always returns ‘0’, indicating that variable rate PCM audio is not available.

Default x200h. Where x is determined by the state of ID[1:0]# input pins. The Extended Audio ID Reg-

ister (Index 28h) is a read only register.

4.15 PCM Front DAC Rate Register (Index 2Ch)

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

SR15 SR14 SR13 SR12 SR11 SR10 SR9 SR8 SR7 SR6 SR5 SR4 SR3 SR2 SR1 SR0

SR[15:0] Front DAC Sample Rate. The SR[15:0] bits are read-only bits, and always read BB80h indicat-

ing 48 kHz sample rate.

Default BB80h. This value corresponds to 48 kHz sample rate.

4.16 PCM L/R ADC Rate Register (Index 32h)

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

SR15 SR14 SR13 SR12 SR11 SR10 SR9 SR8 SR7 SR6 SR5 SR4 SR3 SR2 SR1 SR0

SR[15:0] Left/Right ADC Sample Rate. The SR[15:0] bits are read-only bits, and always read BB80h in-

dicating 48 kHz sample rate.

Default BB80h. This value corresponds to 48 kHz sample rate.

CS4297A

DS318PP6 29

CS4297A

4.17 AC Mode Control Register (Index 5Eh)

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

0000000DDMAMAP0SM1SM00000

DDM DAC Direct Mode. This bit controls the source to the line and alternate line output drivers. When

‘set’, the L/R DACs directly drive the line and alternate line outputs by bypassing the audio mixer. When ‘clear’, the audio mixer is the source for the line and alternate line outputs.

AMAP Audio Slot Mapping. This read/write bit controls whether the CS4297A responds to the Codec

ID based slot mapping as outlined in the AC ’97 2.1 specification. The bit is shadowed in the Extended Audio ID Register (Index 28h). Refer to Table 7 for the slot mapping configurations.

SM[1:0] Slot Map. The SM[1:0] bits define the Slot Mapping for the CS4297A when the AMAP bit is

‘cleared’. Refer to Table 7 for the slot mapping configurations.

Default 0080h

Codec ID Slot Map

Slot

Assignment

Mode

AMAP Mode 000XX 1 3434

AMAP Mode 101XX 1 3434

AMAP Mode 210XX 1 7878

AMAP Mode 311XX 1 6969

Slot Map Mode 0XX00 0 3434

Slot Map Mode 1XX01 0 5656

Slot Map Mode 2XX10 0 7878

Slot Map Mode 3 X X 1 1 0 9 10 9 10

ID1 ID0 SM1 SM0

Table 7. Slot Mapping

AMAP

Slot Assignments

DAC,

SPDIF

LRLR

ADC

4.18 Misc. Crystal Control Register (Index 60h)

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

0000 Reserved 00Reserved0ReservedLOSM

LOSM Loss of SYNC Mute Enable. The LOSM bit controls the loss of SYNC mute function. If this bit

is ‘set’, the CS4297A will mute all analog outputs for the duration of loss of SYNC. If this bit is ‘cleared’, the mixer will continue to function normally during loss of SYNC. The CS4297A expects to sample SYNC ‘high’ for 16 consecutive BIT_CLK periods and then ‘low’ for 240 consecutive BIT_CLK periods, otherwise loss of SYNC becomes true.

Default 0023h

CS4297A

30 DS318PP6

CS4297A

4.19 S/PDIF Control Register (Index 68h)

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

SPEN Val 0 Fs L CC6 CC5 CC4 CC3 CC2 CC1 CC0 Emph Copy /Audio Pro

SPEN S/PDIF Enable. The SPEN bit enables S/PDIF data transmission on the S/PDIF_OUT pin.

The SPEN bit routes the left and right channel data from the AC ’97 controller, the digital mixer, or the digital effects engine to the S/PDIF transmitter block. The actual data routed to the S/PDIF block is controlled through the AMAP/SM[1:0] configuration in the AC Mode Control Register (Index 5Eh).

Val Validity. The V bit is mapped to the V bit (bit 28) of every sub-frame. If this bit is ‘0’, the signal

is suitable for conversion or processing.

Fs Sample Rate. The Fs bit indicates the sampling rate for the S/PDIF data. The inverse of this

bit is mapped to bit 25 of the channel status block. When the Fs bit is ‘clear’, the sampling frequency is 48 kHz. When ‘set’, the sampling frequency is 44.1 kHz. The actual rate at which S/PDIF data are being transmitted solely depends on the master clock frequency of the CS4297A. The Fs bit is merely an indicator to the S/PDIF receiver.

L Generation Status. The L bit is mapped to bit 15 of the channel status block. For category

codes 001xxxx, 0111xxx and 100xxxx, a value of ‘0’ indicates original material and a value of ‘1’ indicates a copy of original material. For all other category codes the definition of the L bit is reversed.

CC[6:0] Category Code. The CC[6:0] bits are mapped to bits 8-14 of the channel status block.

Emph Data Emphasis. The Emph bit is mapped to bit 3 of the channel status block. If the Emph bit

is ‘1’, 50/15us filter pre-emphasis is indicated. If the bit is ‘0’, no pre-emphasis is indicated.

Copy Copyright. The Copy bit is mapped to bit 3 of the channel status block. If the Copy bit is ‘1’

/Audio Audio / Non-Audio. The /Audio bit is mapped to bit 1 of the channel status block. If the /Audio

bit is ‘0’, the data transmitted over S/PDIF is assumed to be digital audio. If the /Audio bit is ‘1’, non-audio data is assumed.

Pro Professional/Consumer. The Pro bit is mapped to bit 0 of the channel status block. If the Pro

bit is ‘0’, consumer use of the audio control block is indicated. If the bit is ‘1’, professional use is indicated.

Default 0000h

For a further discussion of the proper use of the channel status bits see application note AN22: Overview of Digital Audio Interface Data Structures [3].

CS4297A

DS318PP6 31

CS4297A

4.20 Vendor ID1 Register (Index 7Ch)

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

F7 F6 F5 F4 F3 F2 F1 F0 S7 S6 S5 S4 S3 S2 S1 S0

F[7:0] First Character of Vendor ID. With a value of F[7:0] = 43h, these bits define the ASCII ‘C’

character.

S[7:0] Second Character of Vendor ID. With a value of S[7:0] = 52h, these bits define the ASCII ‘R’

character.

Default 4352h. This register contains read-only data.

4.21 Vendor ID2 Register (Index 7Eh)

D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0

T7 T6 T5 T4 T3 T2 T1 T0 0 DID2 DID1 DID0 0 REV2 REV1 REV0

T[7:0] Third Character of Vendor ID. With a value of T[7:0] = 59h, these bits define the ASCII ‘Y’

character.

DID[2:0] Device ID. With a value of DID[2:0] = 001, these bits specify the audio codec is a CS4297A.

REV[2:0] Revision. With a value of REV[2:0] = 001, these bits specify the audio codec revision is ‘A’.

Default 591xh. This register contains read-only data.

The two Vendor ID registers provide a means to determine the manufacturer of the AC ’97 audio codec. The first three bytes of the Vendor ID registers contain the ASCII code for the first three letters of Crystal (CRY). The final byte of the Vendor ID registers is divided into a Device ID field and a Revision field. Table 8 lists the currently defined Device ID’s. Table 9 lists the current revisions of the CS4297A.

DID[2:0] Part Name

000 CS4297

001 CS4297A

010 CS4294/CS4298

011 CS4299

100 CS4201

101 CS4205

Table 8. Device ID with Corresponding Part Number

REV[2:0] Revision

001 A

010 B

011 C

100 D, E, F, G, H

101 K

110 L

Table 9. Revision Values

CS4297A

32 DS318PP6

CS4297A

5. POWER MANAGEMENT

5.1 AC ’97 Reset Modes

The CS4297A supports three reset methods, as defined in the AC ’97 Specification: Cold AC ’97 Re- set, Warm AC ’97 Reset, Register AC ’97 Reset. A Cold Reset results in all AC ’97 logic (registers included) initialized to its default state. A Warm Reset leaves the contents of the AC ’97 register set unaltered. A Register Reset initializes only the AC ’97 registers to their default states.

5.1.1 Cold AC ‘97 Reset

A Cold Reset is achieved by asserting RESET# for a minimum of 1 µs after the power supply rails have stabilized. This is done in accordance with the minimum timing specifications in the AC ’97 Seri- al Port Timing section on page 7. Once deasserted, all of the CS4297A registers will be reset to their default power-on states and the BIT_CLK and SDATA_IN signals will be reactivated.

5.1.2 Wa rm A C ’97 Reset

A Warm Reset allows the AC-link to be reactivated without losing information in the CS4297A registers. A Warm Reset is required to resume from a D3

state, where the AC-link had been halted yet

hot

full power had been maintained. A primary codec Warm Reset is initiated when the SYNC signal is driven high for at least 1 µs and then driven low in the absence of the BIT_CLK clock signal. The BIT_CLK clock will not restart until at least 2 normal BIT_CLK clock periods (162.8 ns) after the SYNC signal is deasserted. A Warm Reset of the secondary codec is recognized when the primary codec on the AC-link resumes BIT_CLK generation. The CS4297A will wait for BIT_CLK to be stable to restore SDATA_IN activity and/or S/PDIF transmission on the following frame.

5.1.3 Register AC ’97 Reset

The third reset mode provides a Register Reset to the CS4297A. This is available only when the CS4297A AC-link is active and the Codec Ready bit is ‘set’. The audio (including extended audio) registers (Index 00h - 38h) and the vendor specific registers (Index 5Ah - 7Ah) are reset to their default states by a write of any value to the Reset Register (Index 00h).

CS4297A

DS318PP6 33

CS4297A

5.2 Powerdown Controls

The Powerdown Control/Status Register (Index 26h) controls the power management func-

tions. The PR[6:0] bits in this register control the internal powerdown states of the CS4297A. Powerdown control is available for individual subsections of the CS4297A by asserting any PRx bit or any combination of PRx bits. Most powerdown states can be resumed by clearing the corresponding PRx bit. Table 10 shows the mapping of the power control bits to the functions they manage.

When PR0 is ‘set’, the L/R ADCs and the Input Mux are shut down and the ADC bit in the Power- down Control/Status Register (Index 26h) is ‘cleared’ indicating the ADCs are no longer in a ready state. The same is true for the DACs, the analog mixers, and the reference voltage (Vrefout). When the PR2 or PR3 bit of the mixer is ‘cleared’, the mixer section will begin a power-on process, and the corresponding powerdown status bit will be ‘set’ when the hardware is ready.

Shutting down the AC-link by ‘setting’ PR4 causes the primary Codec to turn off the BIT_CLK and drive SDATA_IN low. It also ignores SYNC and

SDATA_OUT in their normal capacities. Either a Cold Reset or a Warm Reset is required to restore operation to the CS4297A. A Cold Reset will restore all mixer registers to their power-on default values. A Warm Reset will not alter the values of any mixer register, except clearing the PR4 bit in Powerdown Control/Status Register (Index 26h).

The PR5 bit powers down all analog and digital subsections of the device. A Cold Reset is the only way to restore operation to the CS4297A after a PR5 global powerdown.

The CS4297A does not automatically mute any input or output when the powerdown bits are ‘set’. The software driver controlling the AC ’97 device must manage muting the input and output analog signals before putting the part into any power management state. The definition of each PRx bit may affect a single subsection or a combination of subsections within the CS4297A. Table 11 on page 34 contains the matrix of subsections affected by the respective PRx function. Table 12 on page 34 shows the different operating power consumptions levels for different powerdown functions.

PR Bit Function

PR0 L/R ADCs and Input Mux Powerdown

PR1 Front DACs Powerdown

PR2 Analog Mixer Powerdown (Vref on)

PR3 Analog Mixer Powerdown (Vref off)

PR4 AC-link Powerdown (BIT_CLK off)*

PR5 Internal Clock Disable

PR6 Alternate Line Out Powerdown

* Applies only to primary codec

Table 10. Powerdown PR Bit Functions

CS4297A

34 DS318PP6

CS4297A

PR Bit ADCs DACs Mixer

PR0

•

Alternate

Line Out

Analog

ReferenceACLink

Internal

Clock Off

PR1 • PR2 •• • PR3 ••• • • PR4 • PR5 ••• • • • • PR6 •

Table 11. Powerdown PR Function Matrix

Power State

Full Power + S/PDIF

DVdd

[DVdd=3.3 V]

(mA)

30.1 49.4 37.9

(mA)

DVdd

[DVdd=5 V]

AVd d

(mA)

Full Power 24.5 43.4 37.9

ADCs off (PR0) 21.0 38.1 29.0

DACs off (PR1) 22.1 39.6 31.3

Audio off (PR2) 22.1 39.9 10.7

Vref off (PR3) 18.9 34.8 45 µA

AC-Link off (PR4) 19.3 35.5 37.9

Internal Clocks off (PR5) 11 µA27 µA45 µA

Alt line out off (PR6) 24.5 43.4 36.2

RESET 11 µA27 µA450 µA

Table 12. Power Consumption by Powerdown Mode

Assuming standard resistive load for transformer coupled coaxial S/PDIF output (Rload = 292 Ohm, DVdd = 3.3 V) (Rload = 415 Ohm, DVdd = 5 V). General: I

DVdd S/PDIF

= I

DVdd

+ DVdd/Rload/2

CS4297A

DS318PP6 35

CS4297A

6. ANALOG HARDWARE DESCRIPTION

The analog line-level input hardware consists of four stereo inputs (LINE_IN_L/R, CD_L/GND/R, VIDEO_L/R, and AUX_L/R), two selectable mono microphone inputs (MIC1 and MIC2), and two mono inputs (PC_BEEP and PHONE). The analog line-level output hardware consists of a mono output (MONO_OUT), and dual stereo line outputs (LINE_OUT_L/R and ALT_LINE_OUT_L/R). This section describes the analog hardware needed to interface with these pins. The designs presented in this section comply with specifications detailed in Chapter 17 of the Microsoft PC Design Guide- lines [7] (referred to as PC 99). For EMI reduction techniques refer to the application note N165: CS4297A/CS4299 EMI Reduction Techniques [5].

6.1 Analog Inputs

All analog inputs to the CS4297A, including CD_GND, should be capacitively coupled to the input pins. Unused analog inputs should be tied together and connected through a capacitor to analog ground or tied to the Vrefout pin directly. The maximum allowed voltage for analog inputs, except the microphone input, is 1 V

. For the microphone

RMS

input the maximum allowed voltage depends on the selected boost setting.

6.1.1 Line-Level Inputs

connected to the CD analog source ground. Following the reference designs in Figure 11 and Figure 12 provides extra attenuation of common mode noise coming from the CD-ROM drive, thereby producing a higher quality signal. One percent resistors are recommended since closely matched resistor values provide better common-mode attenuation of unwanted signals. The circuit shown in Figure 11 can be used to attenuate a 2 V shown in Figure 12 can be used for a 1 V

CD input signal by 6 dB. The circuit

RMS

CD in-

put signal.

Ω

6.8 k

Ω

6.8 k

Ω

6.8 k

Figure 10. Line Input (Replicate for Video and Aux)

6.8 k

CD_R

CD_L

CD_COM

(All resistors 1%)

6.8 k

3.4 k

Ω

6.8 k

Ω

AGND

1.0 µF R

1.0

Ω

6.8 k

1.0 µF

2.2 µF

Ω

3.4 k

Ω

CD_R

CD_L

CD_GND

Figure 10 shows circuitry for a line-level stereo in-

Figure 11. Differential 2 V

CD Input

RMS

put. Replicate this circuit for the Line, Video and Aux inputs. This design attenuates the input by

47 k

1.0 µF

2.2 µF

Ω

47 k

Ω

CD_R

CD_L

CD_GND

6 dB, bringing the signal from the PC 99 specified 2 V 1V

, to the CS4297A maximum allowed

RMS

6.1.2 CD Input

CD_R

CD_L

CD_COM

100

Ω

47 k

Ω

The CD line-level input has an extra pin, CD_GND, providing a pseudo-differential input for both CD_L and CD_R. This pin takes the

Figure 12. Differential 1 V

AGND

CD Input

RMS

common-mode noise out of the CD inputs when

CS4297A

Figure 13. Microphone Input

36 DS318PP6

CS4297A

6.1.3 Microphone Inputs

Figure 13 illustrates an input circuit suitable for dynamic and electret microphones. Electret, or phantom-powered, microphones use the right channel (ring) of the jack for power. The design also supports the recommended advanced frequency response for voice recognition as specified in PC 99. Note the microphone input to the CS4297A has an integrated pre-amplifier. Using the 20dB bit in the Microphone Volume Register (Index 0Eh) the pre-amplifier gain can be set to 0 dB or 20 dB. Figure 14 shows an external pre-amplifier circuit for an additional 18 dB gain.

2 k

Ω

Vrefout

0.1 µF

1 µF

47 k

220 pF NPO

0.33 µF X7R

Ω

MIC1 or MIC2

0.33 µF 47

100 pF NPO

47 k

Ω

6.8 K

Ω

MC33078 or MC33178

3.3 µF

6.1.4 PC Beep Input

The PC_BEEP input is useful for mixing the output of the “beeper” (timer chip), provided in most PCs, with the other audio signals. When the CS4297A is held in reset, PC_BEEP is passed directly to the line output. This allows the system sounds or “beeps” to be available before the AC ’97 interface has been activated. Figure 15 illustrates a typical input circuit for the PC_BEEP input. If PC_BEEP is driven from a CMOS gate, the 4.7 kΩ resistor should be tied to analog ground instead of +5VA. Although this input is described for a low-quality “beeper”, it is of the same high-quality as all other analog inputs and may be used for other purposes.

+5VA (Low Noise) or

AGND if CMOS Source

4.7 k

Ω

PC_BEE P

0.1 µF

X7R

PC-BEEP-BUS

47 k

2.7 nF

X7R

Ω

AGND

Figure 15. PC_BEEP Input

+5 VA

U1A

MC33078D

100

AGND

Ω

10 µF

6.8

47 k

Ω

4 3 5 2 1

AGND

2.7 AGND

0.068 µF

X7R

220 pF 220 pF

CGND

5 6

AGND

+5 VA

AGND

220 pF

10 µF

U1B MC33078D

47 k

Ω

AGND

X7R

Ω

1µF

MIC1/MIC2

Figure 14. Microphone Pre-amplifier

CS4297A

Figure 16. Modem Connection

DS318PP6 37

CS4297A

6.1.5 Phone Input

One application of the PHONE input is to interface to the output of a modem analog front end (AFE) device so that modem dialing signals and protocol negotiations may be monitored through the audio system. Figure 16 shows a design for a modem connection where the output is fed from the CS4297A MONO_OUT pin through a divider. The divider ratio shown does not attenuate the signal, providing an output voltage of 1 V

. If a lower

RMS

output voltage is desired, the resistors can be replaced with appropriate values, as long as the total load on the output is kept greater than 10 kΩ. The PHONE input is divided by 6 dB to accommodate a line-level source of 2 V

RMS

6.2 Analog Outputs

The analog line-level output section provides two stereo outputs and a mono output. The LINE_OUT_L/R, ALT_LINE_OUT_L/R, and

MONO_OUT pins require 680 pF to 1000 pF NPO capacitors between the corresponding pin and analog ground. Each analog output is DC-biased up to the Vrefout signal reference, nominally 2.3 V. This requires the outputs be AC-coupled to external circuitry (AC load must be greater than 10 kΩ) or DC coupled to a buffer op-amp biased at Vrefout.

6.2.1 Stereo Outputs

See Figure 18 for a line-level stereo output reference design. See Figure 17 for a recommended headphone stereo output reference design.

6.2.2 Mono Output

The mono output, MONO_OUT, can be either a sum of the left and right output channels, attenuated by 6 dB to prevent clipping at full scale, or the selected Mic signal. The mono out channel can drive the PC internal mono speaker using an appropriate buffer circuit

PHONE

MONO_OUT

6.8 k

Ω

1.0 µF

0 Ω

6.8 k

Ω

AGND AGND

ALT_LINE_OUT_R

Vrefout

ALT_LINE_OUT_L

Figure 17. Alternate Line Output as Headphone Output

1.0 µF

47 k

Ω

1000 pF

1000 pF NPO

AGND

PHONE

MONO_OUT

27 k

Ω

27 k

Ω

1000 pF NPO

39 k

TDA1308

39 k

Ω

22 pF NPO

Ω

TDA1308

ALT_LINE_OUT_R

ALT_LINE_OUT_L

VREFOUT

1000 pF

220 µF

22 pF NPO

27 k

Ω

1000 pF

NPO

AGND

0.1 µF

1 µF

Y5V

AGND

ELEC

220 µF

39 k

Ω

ELEC 22 pF NPO

TDA1308

Ω

HP_OUT_R

1/4 WATT

Ω

HP_OUT_L

1/4 WATT

47 k

Ω

AGND

Figure 18. Stereo Output

220 µF

ELEC

220

ELEC

47 k

10 Ω

Watt

1/4

AGND

47 k

1/4

10 Ω

Watt

Ω

Headphone Out

CS4297A

38 DS318PP6

CS4297A

6.3 Miscellaneous Analog Signals

The AFLT1 and AFLT2 pins must have a 1000 pF NPO capacitor to analog ground. These capacitors provide a single-pole low-pass filter at the inputs to the ADCs. This makes low-pass filters at each analog input pin unnecessary.

The REFFLT pin must have a 1 µF and a 0.1 µF capacitor connected to analog ground with a short, wide trace to this pin (see Figure 21 in Section 8, Grounding and Layout, for an example). The 1 µF capacitor must not be replaced with any value higher than 1 µF. No other connection should be made, as any coupling onto this pin will degrade the analog performance of the CS4297A. Likewise, digital signals should be kept away from REFFLT for similar reasons.

The Vrefout pin is typically 2.3 V and provides a common mode signal for single-supply external circuits. Vrefout only supports light DC loads and should be buffered if AC loading is needed. For typical use the Vrefout pin should have a 1 µF and a 0.1 µF capacitor connected to analog ground.

6.4 Power Supplies

The power supplies providing analog power should be as clean as possible to minimize coupling into the analog section which could degrade analog performance. The analog power pins, AVdd1 and AVdd2, supply power to all the analog circuitry on the CS4297A. The +5 V analog supply should be generated from a linear voltage regulator (7805 type) connected to a +12 V supply. This helps isolate the analog circuitry from noise typically found on +5 V digital supplies. A typical voltage regulator circuit for analog power using a MC78M05CDT +5 V regulator is shown in Figure 19. The digital power pins, DVdd1 and DVdd2, should be connected to the same digital supply as the controller AC-link interface. The digital interface on the CS4297A may operate at either +3.3 V or +5 V and proper connection of these pins will depend on the digital power supply of the controller.

6.5 Reference Design

See Section 11 for a CS4297A reference design.

+12VD

MC78M05CDT

Y5V

0.1µF

ELEC 10µF

Figure 19. Voltage Regulator

GND

OUT

Y5V

0.1µF

+5VA

AGNDDGND

ELEC 10µF

CS4297A

DS318PP6 39

CS4297A

7. SONY/PHILIPS DIGITAL INTERFACE (S/PDIF)

The S/PDIF digital output is used to interface the CS4297A to consumer audio equipment external to the PC. This output provides an interface for storing digital audio data or playing digital audio data to digital speakers. Figure 20 illustrates the circuits necessary for implementing the IEC-958 optical or consumer interface. For further information on S/PDIF operation see application note AN22: Over- view of Digital Audio Interface Data Structures [3]. For further information on S/PDIF recommended transformers see application note AN134: AES and S/PDIF Recommended Transformers [4].

8. GROUNDING AND LAYOUT

Figure 21 on page 40 shows the conceptual layout for the CS4297A. The decoupling capacitors should be located physically as close to the pins as possible. Also note the connection of the REFFLT decoupling capacitors to the ground return trace connected directly to the ground return pin, AVss1.

cuitry. All analog components and traces should be located over the analog ground plane and all digital components and traces should be located over the digital ground plane.

The common connection point between the two ground planes (required to maintain a common ground voltage potential) should be located under the CS4297A. The AC-link digital interface connection traces should be routed such that the digital ground plane lies underneath these signals (on the internal ground layer). This applies along the entire length of these traces from the AC ’97 controller to the CS4297A.

Refer to the Application Note AN18: Layout and

Design Rules for Data Converters and Other Mixed Signal Devices [2] for more information on

layout and design rules.

It is strongly recommended that separate analog and digital ground planes be used. Separate ground planes keep digital noise and return currents from modulating the CS4297A ground potential and degrading performance. The digital ground pins should be connected to the digital ground plane and kept separate from the analog ground connections of the CS4297A and any other external analog cir-

SPDO/SDO2

DVdd

3.3V

247.5

107.6

S/PDIF_OUT

375

Ω Ω

93.75

Ω

DGND

Figure 20. S/PDIF Output

+5V_PCI

0.1µF

DGND

SPDO/SDO2

8.2 k

Ω

TOTX-173

DGND

40 DS318PP6

CS4297A

Via to +5VA

0.1 µF

Y5V

AVss2

AVdd2

1000 pF NPO

AFLT2

Via to Analog Ground

Digital

Ground

Via to Digital Ground

Vrefout to via

AFLT1

REFFLT

AVss1

Via to Analog Ground

Analog

Ground

µF

Via to +5VA

0.1 µF Y5V

AVdd1

Pin 1

DVdd1

Via to +5VD or +3.3VD

0.1 µF Y5V

DVss1

DVss2

0.1 µF Y5V

DVdd2

Via to +5VD or +3.3VD

Figure 21. Conceptual Layout for the CS4297A

9. PIN DESCRIPTIONS

DS318PP6 41

CS4297A

ALT_LINE_OUT_L

d d V A

s2 s

ID1#

EAPD

S/PDIF_OUT

48 47 46 45 44 43 42 41 40 39 38 37

ID0#

C N

ALT_LINE_OUT_R

T U O

_ O N

CS4297A

DVdd1

XTL_IN

XTL_OUT

DVss1

SDATA_OUT

BIT_CLK

DVss2

SDATA_IN

DVdd2

SYNC

RESET#

PC_BEEP

1 2

3 4

6 7

8 9 10 11

13 14 15 16 17 18 19 20 21 22 23 24

Figure 22. Pin Locations for the CS4297A

PHON

(48-Pin LQFP)

L _

X AU

CS4297A-xQ

R _

O_ E D

I V

R O_

E D

I V

_ D C

CD_GN

CD_

1 C

I M

2 C

I M

L _

I _

I L

36 35 34 33

31 30

29 28 27 26 25

R _

I _

I L

LINE_OUT_R L

INE_O FLTO FLTI FLT3D BPCFG AFLT2 AFLT1 Vrefout REFFLT AVss1 AVdd1

UT_L

Audio I/O

42 DS318PP6

CS4297A

PC_BEEP - Analog Mono Source, Input, Pin 12

The PC_BEEP input is intended to allow the PC system POST (Power On Self-Test) tones to pass through to the audio subsystem. The PC_BEEP input has two connections: the first connection is to the analog output mixer, the second connection is directly to the LINE_OUT stereo outputs. While the RESET# pin is actively being asserted and the BCFG pin is left floating, the PC_BEEP bypass path to the LINE_OUT outputs is enabled. While the CS4297A is in normal operation mode, with RESET# deasserted or BCFG grounded, PC_BEEP is a monophonic source to the analog output mixer. The maximum allowable input is 1 V reference and requires AC-coupling to external circuitry. If this input is not used, it should be connected to the Vrefout pin or AC-coupled to analog ground.

PHONE - Analog Mono Source, Input, Pin 13

This analog input is a monophonic source to the analog output mixer. It is intended to be used as a modem subsystem input to the audio subsystem. The maximum allowable input is 1 V This input is internally biased at the Vrefout voltage reference and requires AC-coupling to external circuitry. If this input is not used, it should be connected to the Vrefout pin or AC-coupled to analog ground.

MIC1 - Analog Mono Source, Input, Pin 21

(sinusoidal). This input is internally biased at the Vrefout voltage

RMS

CS4297A

(sinusoidal).

RMS

This analog input is a monophonic source to the analog output mixer. It is intended to be used as a desktop microphone connection to the audio subsystem. The CS4297A internal mixer’s microphone input is MUX selectable with either MIC1 or MIC2 as the input. The maximum allowable input is 1 V (sinusoidal). This input is internally biased at the Vrefout voltage reference and requires AC-coupling to external circuitry. If this input is not used, it should be connected to the Vrefout pin or AC-coupled to analog ground.

MIC2 - Analog Mono Source, Input, Pin 22

This analog input is a monophonic source to the analog output mixer. It is intended to be used as an alternate microphone connection to the audio subsystem. The CS4297A internal mixer’s microphone input is MUX selectable with either MIC1 or MIC2 as the input. The maximum allowable input is 1 V (sinusoidal). This input is internally biased at the Vrefout voltage reference and requires AC-coupling to external circuitry. If this input is not used, it should be connected to the Vrefout pin or AC-coupled to analog ground.

LINE_IN_L, LINE_IN_R - Analog Line Source, Inputs, Pins 23 and 24

These inputs form a stereo input pair to the CS4297A. The maximum allowable input is 1 V (sinusoidal). These inputs are internally biased at the Vrefout voltage reference and require AC-coupling to external circuitry. If these inputs are not used, they should both be connected to the Vrefout pin or both AC-coupled, with separate AC-coupling caps, to analog ground.

CD_L, CD_R - Analog CD Source, Inputs, Pins 18 and 20

These inputs form a stereo input pair to the CS4297A. It is intended to be used for the Red Book CD audio connection to the audio subsystem. The maximum allowable input is 1 V inputs are internally biased at the Vrefout voltage reference and require AC-coupling to external circuitry. If these inputs are not used, they should both be connected to the Vrefout pin or both AC-coupled, with separate AC-coupling caps, to analog ground.

(sinusoidal). These

RMS

CD_GND - Analog CD Common Source, Input, Pin 19

This analog input is used to remove common mode noise from Red Book CD audio signals. The impedance on the input signal path should be one half the impedance on the CD_L and CD_R input paths. This pin requires AC-coupling to external circuitry. If this input is not used, it should be connected to the Vrefout pin or AC-coupled to analog ground.

VIDEO_L, VIDEO_R - Analog Video Audio Source, Inputs, Pins 16 and 17

DS318PP6 43

CS4297A

These inputs form a stereo input pair to the CS4297A. It is intended to be used for the audio signal output of a video device. The maximum allowable input is 1 V internally biased at the Vrefout voltage reference and require AC-coupling to external circuitry. If these inputs are not used, they should both be connected to the Vrefout pin or both AC-coupled, with separate AC-coupling caps, to analog ground.

AUX_L, AUX_R - Analog Auxiliary Source, Inputs, Pins 14 and 15

CS4297A

(sinusoidal). These inputs are

RMS

LINE_OUT_L, LINE_OUT_R - Analog Line-Level, Outputs, Pins 35 and 36

These signals are analog outputs from the stereo output mixer. The full-scale output voltage for each output is nominally 1 V reference and require either AC-coupling to external circuitry or DC-coupling to a buffer op-amp biased at the Vrefout voltage. These pins need a 680-1000 pF NPO capacitor attached to analog ground.

ALT_LINE_OUT_L, ALT _LINE_OUT_R - Analog Alternate Line-Level, Outputs, Pins 39 and 41

MONO_OUT - Analog Mono Line-Level, Output, Pin 37

This signal is an analog output from the stereo-to-mono mixer or MIC1/2. The full-scale output voltage for this output is nominally 1 V reference and requires either AC-coupling to external circuitry or DC-coupling to a buffer op-amp biased at the Vrefout voltage. This pin needs a 680-1000 pF NPO capacitor attached to analog ground.

(sinusoidal). These outputs are internally biased at the Vrefout voltage

RMS

(sinusoidal). These outputs are internally biased at the Vrefout voltage

RMS

(sinusoidal). This output is internally biased at the Vrefout voltage

RMS

Clock and Configuration

XTL_IN - Crystal Input/Clock Input, Pin 2

In primary mode this pin requires either a 24.576 MHz crystal, with the other pin attached to XTL_OUT, or an external CMOS clock. The crystal frequency must be 24.576 MHz and designed for fundamental mode, parallel resonance operation. If an external CMOS clock is used to drive this pin, it must run at

24.576 MHz. In secondary mode all timing is derived from the BIT_CLK input signal and this pin should be left floating.

XTL_OUT - Crystal Output, Pin 3

This pin is used when a crystal is placed between XTL_OUT and XLT_IN. If an external 24.576 MHz clock is used on XTL_IN, this pin must be left floating with no traces or components connected to it. In secondary mode this pin should be left floating.

ID1#, ID0# - Codec ID, Inputs, Pins 45 and 46

These pins select the Codec ID and mode of operation for the CS4297A. They are only sampled after the rising edge of RESET#. These pins are internally pulled up to the digital supply voltage and should be left floating for logic ‘0’ or tied to digital ground for logic ‘1’. When both pins are left floating the CS4297A is the primary codec. If either or both pins are tied to ground the CS4297A is a secondary codec.

Analog Reference, Filters, and Configuration

44 DS318PP6

CS4297A

REFFLT - Internal Reference Voltage, Input, Pin 27

This signal is the voltage reference used internal to the CS4297A. A 0.1 µF and a 1.0 µF (must not be larger than 1 µF) capacitor with short, wide traces must be connected to this pin. No other connections should be made to this pin.

Vrefout - Voltage Reference, Output, Pin 28

All analog inputs and outputs are centered around Vrefout, nominally 2.3 Volts. This pin may be used to level shift external circuitry. This pin cannot drive any DC loads, thus any external loading must be buffered.

AFLT1 - Left ADC Channel Antialiasing Filter, Input, Pin 29

This pin needs a 1000 pF NPO capacitor connected to analog ground.

AFLT2 - Right ADC Channel Antialiasing Filter, Input, Pin 30

This pin needs a 1000 pF NPO capacitor connected to analog ground.

FLTI, FLTO - 3D Filter, Input, Pin 33 and 34

A 1000 pF capacitor must be connected between FLTI and FLTO if the 3D function is used.

FLT3D - 3D Filter, Input, Pin 32

A 0.01 µF capacitor must be connected from this pin to AGND if the 3D function is used.

BCFG - Beep Configuration, Input, Pin 31

This pin is the configuration control for the PC_BEEP bypass path. If this pin is grounded, the bypass path is disabled. If this pin is left floating, the PC_BEEP bypass path is enabled.

CS4297A

Misc. Digital Interfaces

S/PDIF_OUT - Sony/Philips Digital Interface, Output, Pin 48

This pin generates the S/PDIF digital output from the CS4297A when the SPEN bit in the S/PDIF Control Register (Index 68h) is ‘set’. This output may be used to directly drive a resistive divider and

coupling transformer to an RCA-type connector for use with consumer audio equipment.

EAPD - External Amplifier Powerdown, Output, Pin 47

This pin is used to control the powerdown state of an audio amplifier external to the CS4297A. The output is controlled by the EAPD bit in the Powerdown Ctrl/Stat Register (Index 26h). It is driven as a normal CMOS output and defaults low (‘0’) upon power-up.

AC-Link

DS318PP6 45

CS4297A

RESET# - AC ’97 Chip Reset, Input, Pin 11

This active low signal is the asynchronous Cold Reset input to the CS4297A. The CS4297A must be reset before it can enter normal operating mode.

SYNC - AC-Link Serial Port Sync pulse, Input, Pin 10

This signal is the serial port timing signal for the AC-link. Its period is the reciprocal of the maximum sample rate, 48 kHz. The signal is generated by the controller, synchronous to BIT_CLK. SYNC is an asynchronous input when the CS4297A is configured as a primary audio codec and is in a PR4 powerdown state. A series terminating resistor of 47 Ω should be connected on the signal near the SYNC source.

BIT_CLK - AC-Link Serial Port Master Clock, Input/Output, Pin 6

This input/output signal controls the master clock timing for the AC-link. In primary mode, this signal is a

12.288 MHz output clock derived from a 24.576 MHz crystal on the XTL_IN input clock. When the CS4297A is in secondary mode, this signal is an input which controls the AC-link serial interface and generates all internal clocking including the AC-link serial interface timing and the analog sampling clocks. A series terminating resistor of 47 Ω should be connected on this signal close to the CS4297A in primary mode or close to the BIT_CLK source in secondary mode.

CS4297A

SDATA_OUT - AC-Link Serial Data Input Stream to AC ’97, Input, Pin 5

This input signal receives the control information and digital audio output streams. The data is clocked into the CS4297A on the falling edge of BIT_CLK. A series terminating resistor of 47 Ω should be connected on this signal near the controller.

SDATA_IN - AC-Link Serial Data Output Stream from AC ’97, Output, Pin 8

This output signal transmits the status information and digital audio input streams from the ADCs. The data is clocked out of the CS4297A on the rising edge of BIT_CLK. A series terminating resistor of 47 Ω should be connected on this signal as close to the CS4297A as possible.

Power Supplies

DVdd1, DVdd2 - Digital Supply Voltage, Pins 1 and 9

Digital supply voltage for the AC-link section of the CS4297A. These pins can be tied to +5 V digital or to +3.3 V digital. The CS4297A and controller AC-link should share a common digital supply

DVss1, DVss2 - Digital Ground, Pins 4 and 7

Digital ground connection for the AC-link section of the CS4297A. These pins should be isolated from analog ground currents.

AVdd1, AVdd2 - Analog Supply Voltage, Pins 25 and 38

Analog supply voltage for the analog and mixed signal sections of the CS4297A. These pins must be tied to the analog +5 V power supply. It is strongly recommended that +5 V be generated from a voltage regulator to ensure proper supply currents and noise immunity from the rest of the system.

AVss1, AVss2 - Analog Ground, Pins 26 and 42

Ground connection for the analog, mixed signal, and substrate sections of the CS4297A. These pins should be isolated from digital ground currents.

10. PARAMETER AND TERM DEFINITIONS

46 DS318PP6

CS4297A

AC ’97 Specification

Refers to the Audio Codec ’97 Component Specification Ver 2.1 published by the Intel

AC ’97 Controller or Controller

Refers to the control chip which interfaces to the audio codec AC-link. This has been also called DC ’97 for Digital Controller ’97 [6].

AC ’97 Registers or Codec Registers

Refers to the 64-field register map defined in the AC ’97 Specification.

ADC

Refers to a single Analog-to-Digital converter in the CS4297A. “ADCs” refers to the stereo pair of Analog-to-Digital converters. The CS4297A ADCs have 18-bit resolution.

Codec

Refers to the chip containing the ADCs, DACs, and analog mixer. In this data sheet, the codec is the CS4297A.

DAC

CS4297A

Corporation [6].

Refers to a single Digital-to-Analog converter in the CS4297A. “DACs” refers to the stereo pair of Digital-to-Analog converters. The CS4297A DACs have 20-bit resolution.

dB FS A

dB FS is defined as dB relative to full-scale. The “A” indicates an A weighting filter was used.

Differential Nonlinearity

The worst case deviation from the ideal code width. Units in LSB.

Dynamic Range (DR)

DR is the ratio of the RMS full-scale signal level divided by the RMS sum of the noise floor, in the presence of a signal, available at any instant in time (no change in gain settings between measurements). Measured over a 20 Hz to 20 kHz bandwidth with units in dB FS A.

FFT

Fast Fourier Transform.

Frequency Response (FR)

FR is the deviation in signal level verses frequency. The 0 dB reference point is 1 kHz. The amplitude corner, Ac, lists the maximum deviation in amplitude above and below the 1 kHz reference point. The listed minimum and maximum frequencies are guaranteed to be within the Ac from minimum frequency to maximum frequency inclusive.

Sampling Frequency.

Interchannel Gain Mismatch

For the ADCs, the difference in input voltage to get an equal code on both channels. For the DACs, the difference in output voltages for each channel when both channels are fed the same code. Units are in dB.

Interchannel Isolation

DS318PP6 47

CS4297A

The amount of 1 kHz signal present on the output of the grounded AC-coupled line input channel with 1 kHz, 0 dB, signal present on the other line input channel. Units are in dB.

Line-level

Refers to a consumer equipment compatible, voltage driven interface. The term implies a low driver impedance and a minimum 10

Paths

A-D: Analog in, through the ADCs, onto the serial link.

D-A: Serial interface inputs through the DACs to the analog output.

A-A: Analog in to Analog out (analog mixer).

PC 99

kΩ load impedance.

CS4297A

Refers to the PC 99 System Design Guide published by the Microsoft

PLL

Phase Lock Loop. Circuitry for generating a desired clock from an external clock source.

Resolution

The number of bits in the output words to the DACs, and in the input words to the ADCs.

Signal to Noise Ratio (SNR)

SNR, similar to DR, is the ratio of an arbitrary sinusoidal input signal to the RMS sum of the noise floor, in the presence of a signal. It is measured over a 20 Hz to 20 kHz bandwidth with units in dB.

S/PDIF

Sony/Phillips Digital Interface. This interface was established as a means of digitally interconnecting consumer audio equipment. The documentation for S/PDIF has been superseded by the IEC-958 consumer digital interface document.

SRC

Sample Rate Converter. Converts data derived at one sample rate to a differing sample rate. The CS4297A operates at a fixed sample frequency of 48 kHz. The internal sample rate converters are used to convert digital audio streams playing back at other frequencies to 48 kHz.

Corporation [7].

Total Harmonic Distortion plus Noise (THD+N)

THD+N is the ratio of the RMS sum of all non-fundamental frequency components, divided by the RMS full-scale signal level. It is tested using a -3 dB FS input signal and is measured over a 20 Hz to 20 kHz bandwidth with units in dB FS.

11. REFERENCE DESIGN

48 DS318PP6

CS4297A

LINE OUT

ELEC

C15 10uF

ABITCLK

ASDIN

ASYNC

ASDOUT

ARST#

AC LINK

PCI Audio Controller

or ICH Controller

C11

0.1uF

X7R

C10

0.1uF

X7R

+5VA+12V

U1 M C78M05ACDT

10uF

ELEC

0.1uF

X7R

OUT

GND

+3.3VD

0.1uF

X7R

AGND

0.1uF

X7R

10uF

ELEC

0.1uF

X7R

AGND

R8 47

R7 47

AVdd2

AVdd1

BIT_CLK

AVss2

AVss1

CS4297A

DVdd2

DVdd1

DVss1

DVss2

SYNC

RESET#

SDATA_IN

SDATA_OUT

LINE_OUT_R

LINE_OUT_L

PC_BEEP

AUX_L

AUX_R

CD_R

CD_GND

DGND

PHONO-1/8

R13

R12

ELEC

C17 10uF

MONO_OUT

ALT_LINE_OUT_L

ALT_LINE_OUT_R

LINE_IN_L

LINE_IN_R

MIC1

CD_L

AGND

220K

AGND

220K

AGND

TOTX-173

C18

NPO

1000pF

AGND

C19

NPO

1000pF

AGND

nc6

nc7

BCFG

MIC2

nc5

EAPD

ID0#

ID1#

S/PDIF_OUT

XTL_OUT

XTL_IN

FLTO

FLTI

FLT3D

AFLT2

AFLT1

PHONE

Vrefout

REFFLT

VIDEO_R

VIDEO_L

C29

1000pF

C28

0.01uF

C27

1000pF

C26

1000pF

C25

0.1uF

C24

1uF

S/PDIF OUT

+5VD

NPO

X7R

NPO

X7R

Y5V

DGND

R21

C31

0.1uF

X7R

DGND

C34

22pF

NPO

DGND

24.576 MHz

(50 PPM)

C33

22pF

NPO

DGND

AGND

Figure 23. CS4297A Reference Design

C23

0.1uF

X7R

60 mil trace

GND_TIE

DGND

Tie at one point only

under the codec

Y5V

C30

C32

10uF

ELEC

PHONO-1/8

AGND

X7R

C1 0.1uF

2700pF

X7R

6.8K

R1 47K

PC SPEAKER

C22

1uF

Y5V

R19 1.5K

R18 2.2K

MIC IN

1uF

R20 100

1uF

Y5V

1uF

Y5V

AGND

R3 6. 8K

AGND

DGND

2X1HDR-SN/PB

AUX IN

C12

R4 6. 8K

R6 6. 8K

R5 6. 8K

1uF

Y5V

C13

R9 100K

AGND

4X1HDR-AU

CD IN

1uF

Y5V

1uF

Y5V

C16

C14

R10 100K

R11 100K

4X1HDR-AU

Y5V

C20

R14 6.8K

AGND

LINE IN

Y5V

C21

R16 6.8K

R15 6.8K

PHONO-1/8

+5VA

R17 6.8K

AGND

12. REFERENCES

DS318PP6 49

CS4297A

1) Cirrus Logic, Audio Quality Measurement Specification, Version 1.0, 1997

http://www.cirrus.com/products/papers/meas/meas.html

CS4297A

2) Cirrus Logic, AN18: Layout and Design Rules for Data Converters and Other Mixed Signal Devices Version 6.0, February 1998

3) Cirrus Logic, AN22: Overview of Digital Audio Interface Data Structures

4) Cirrus Logic, AN134: AES and S/PDIF Recommended Transformers

5) Cirrus Logic, AN165: CS4297A/CS4299 EMI Reduction Techniques

6) Intel

, Audio Codec ’97 Component Specification, Revision 2.1, May 1998

, Version 2.0, February 1998

, Version 2, April 1999

, Version 1.0, September 1999

http://developer.intel.com/ial/scalableplatforms/audio/index.htm

7) Microsoft

, PC 99 System Design Guide, Version 1.0, July 1999

http://www.microsoft.com/hwdev/desguid/

8) Intel

82801AA (ICH) and 82801AB (ICH0) I/O Controller Hub, June 1999

http://developer.intel.com/design/chipsets/datashts/290655.htm

13. PACKAGE DIMENSIONS

48 DS318PP6

CS4297A

50 DS318PP6

CS4297A

48L LQFP PACKAGE DRAWING

CS4297A

∝

INCHES MILLIMETERS

DIM MIN NOM MAX MIN NOM MAX

A --- 0.055 0.063 --- 1.40 1.60

A1 0.002 0.004 0.006 0.05 0.10 0.15

B 0.007 0.009 0.011 0.17 0.22 0.27 D 0.343 0.354 0.366 8.70 9.0 BSC 9.30

D1 0.272 0.28 0.280 6.90 7.0 BSC 7.10

E 0.343 0.354 0.366 8.70 9.0 BSC 9.30

E1 0.272 0.28 0.280 6.90 7.0 BSC 7.10

e* 0.016 0.020 0.024 0.40 0.50 BSC 0.60

L 0.018 0.24 0.030 0.45 0.60 0.75

∝

* Nominal pin pitch is 0.50 mm

0.000° 4° 7.000° 0.00° 4° 7.00°

Controlling dimension is mm. JEDEC Designation: MS022

• Notes •

DS318PP6 51

CS4297A

52 DS318PP6

CS4297A

52 DS318PP6

CS4297A

Cirrus Logic CS4297A User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual