CMI8768

PCI 8CH Integrated Sound Chip

FEATURES
DESCRIPTION
 The global first 8CH single sound chip with
CMI8768 is the first high performance (SNR~100dB)
embedded codec
8CH PCI integrated sound chip compatible with PCI
 Full-duplex 8CH DAC/2CH ADC
V.2.2 specification in the world. With 16bit/96K
 Supports 96K/16bit playback; 48K/16bit
digital/analog playback capability and versatile
recording
driver support, CMI8768 is designed delicately for
 CE level high-quality Signal-to-Noise Ratio (SNR)~
advanced consumer PC sound card/media
100dB
center/mainboard/desktop/embedded
 Integrated S/PDIF transmitter supports
system/server audio applications. Through
44.1k/48k/96KHz sample rate (96k not available
integrating a full-duplex 8/2 CODEC and S/PDIF
on Windows Vista)
transmitter/receiver, CMI8768 consequently saves
 PCI Rev. 2.2 compliant with bus mastering modes
much BOM cost for customers. CMI8768, bundled
 Supports the latest Dolby® Digital EX and DTS®
with C-Media friendly and high add-on value driver,
ES 6.1/7.1CH DVD soundtrack playback
provides the most economic and ideal audio
 Two S/PDIF inputs for optical and coaxial
solution with the best value-price ratio.
connectors individually
Integrated S/PDIF transmitter can deliver 5.1
 Built-in earphone buffer at Front-Out pins (32Ω
Dolby® Digital/DTS® , or 6.1/7.1 Dolby® Digital
loading)
Surround EX/DTS ES DVD soundtracks and
 One GPIO (General purpose I/O) support
up-to-96KHz high-definition audio stream to
external receiver satisfying audio enthusiasts and
pioneers.

BLOCK DIAGRAM
CMI 8768

ZV Port
DMA Engine
PCI Local Bus

& IRQ
Control
PCI S/PDIF I/O Digital I/O

Interface

8CH DAC
Audio
DSP Engine 2CH ADC

8CH Analog Outputs

HP AMP

PLL Analog
MPU-401 Line/CD/Aux Inputs
(14.318MHz) Mixer
Port
Microphone/PCBeep

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CMI8768
PCI 8CH Integrated Sound Chip

TABLE OF CONTENTS

Revision History....................................................................................... 3
1. Description and Overview ..................................................................... 4
2. Features .......................................................................................... 5
3. Block Diagram ................................................................................... 7
4. Pin Assignment .................................................................................. 8
5. Pin Description .................................................................................. 9
5.1 Digital I/O ......................................................................................................... 9
5.2 Analog I/O ........................................................................................................ 10
5.3 Power & Ground ................................................................................................. 10
5.4 NC .................................................................................................................. 11
6. Electrical Characteristics ..................................................................... 12
6.1 Maximum Ratings ................................................................................................ 12
6.2 Recommended Operation Conditions ........................................................................ 12
6.3 Power Consumption ............................................................................................. 12
6.4 Digital Characteristics .......................................................................................... 12
6.5 AC Characteristics .............................................................................................. 13
7. Mechanical Dimensions........................................................................ 16

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CMI8768
PCI 8CH Integrated Sound Chip

Revision History

Date Rev. Release Note

2003/06/13 Rev. 0.1 Preliminary vision

2003/07/17 Rev. 0.2 Change feature and pin description

2003/10/13 Rev. 0.3 Add analog performance data

2004/03/31 Rev. 0.9 Change product name from 8768+ to 8768

Update feature/overview description (Support 96K/24Bit output)

Clarify block diagram (no legacy/SBPRO support)

Correct pin function (#125 XS6CH=>GND; #90-97 XGD0-XGD7=>NC)

Add Electrical Characteristics data and update analog performance

2004/12/01 Rev. 1.0 Correct pin #59 EXTBASS type from analog output to input

Add pin #62 description: XINTREF => Internal reference voltage

Change feature description

Clarify DirectX9.0 installed is required for 8ch playback support on Windows

Indicate pin#9 IDSEL can works only with A16~31

Modify SPDIF-Out high voltage from VDD to 5V

2008/4/18 Rev. 1.1 Change the spec of resolution support

Highlight the current spec limitations on Microsoft Windows Vista

2008/10/08 Rev. 1.2 Remove Sensaura support

2010/04/28 Rev. 1.3 Format Modification

2010/05/07 Rev. 1.4 Modify pin 71, 72 as input

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CMI8768
PCI 8CH Integrated Sound Chip

1. Description and Overview

CMI8768 is the first high performance (SNR~100dB) 8CH PCI integrated sound chip compatible with PCI
V.2.2 specification in the world. With 16bit/96K digital/analog playback capability and versatile driver
support, CMI8768 is designed delicately for advanced consumer PC sound card/media
center/mainboard/desktop/embedded system/server audio applications. Through integrating a
full-duplex 8/2 CODEC and S/PDIF transmitter/receiver, CMI8768 consequently saves much BOM cost for
customers. CMI8768, bundled with C-Media friendly and high add-on value driver, provides the most
economic and ideal audio solution with the best value-price ratio.

Integrated S/PDIF transmitter can deliver 5.1 Dolby® Digital/DTS® , or 6.1/7.1 Dolby® Digital Surround
EX/DTS ES DVD soundtracks and up-to-96KHz high-definition audio stream to external receiver satisfying
audio enthusiasts and pioneers. The S/PDIF-Out data can meet the requirement of SCMS (Serial Copy
Management System) for digital content serial copy protection legislated by consumer audio industry.
CMI8768 also supports MPU-401 MIDI port for external musical instrument input.

Figure 1. Graphic User Interface Samples-- Main Setting & Mixer

Being compatible with various industrial standards for gaming such as

EAX™ 1.0&2.0, Direct Sound™ 3D(not available due to Windows Vista’s architecture change), C-Media
CMI8768 can provide enthusiastic gamers breathtaking sound experience in gaming.

C-Media proprietary Xear 3DTM sound technology empowers users to shift virtual speakers anywhere they
want for optimizing the personal sound field. Virtual speakers can even deliver up-to-7.1 channel surround

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CMI8768
PCI 8CH Integrated Sound Chip

sounds over only 2 physical speakers or headphones. C-Media unique Magic VoiceTM functionality can
reform your microphone voice through the recording process delivering amazing disguise effects for fun in
many applications, such as Internet phone, messenger, online games, etc. Microphone echo and
key-shifting features are well designed for karaoke application. Other sound effects like 10-band Equalizer
and 27 environment effects can enrich user’s audio experience and enjoyment.

Figure 2. Graphic User Interface Samples—Virtual Speaker SHIFTER & Sound Effect

Figure 3. Graphic User Interface Samples—Karaoke & Magic Voice & Information

2. Features
 The global first 8CH single sound chip with embedded codec
 Full-duplex 8CH DAC/2CH ADC
 Supports 96K/16bit playback; 48K/16bit recording
 CE level high-quality Signal-to-Noise Ratio (SNR)~ 100dB
 Integrated S/PDIF transmitter supports 44.1k/48k/96KHz sample rate (96k not available on Windows

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CMI8768
PCI 8CH Integrated Sound Chip

Vista)
 PCI Rev. 2.2 compliant with bus mastering modes
 Supports the latest Dolby® Digital EX and DTS® ES 6.1/7.1CH DVD soundtrack playback
 Two S/PDIF inputs for optical and coaxial connectors individually
 Built-in earphone buffer at Front-Out pins (32Ω loading)
 One GPIO (General purpose I/O) support
 External EEPROM Interface for SVID\SSID R/W purpose
 Supports MPU401 MIDI UART port
 DirectSound™ 3 HW acceleration compliant (not available on Vista yet)
 Power On/Off anti-pop circuit reference design
 ACPI compliant power down management
 Zoomed Video Port support
 Industrial standard QFP-128 package
 Almost pin-to-pin compatible with CMI8738 series
 Digital power = 3.3V & 5V, Analog power = 5V

Valuable S/W:
 C-Media Xear 3D™ 7.1 Virtual Speaker SHIFTER technology

 Interesting Magic VoiceTM feature to disguise users’ voice tone in all IP phones (Skype, MSN,

Yahoo,…), online games, messenger, and Internet DJ/broadcasting applications

 Unique Karaoke functionality: Mic Echo, Key-shifting, Vocal Cancellation

 Supports most industrial standards of PC 3D sound for gaming, including EAX™ 1.0&2.0, and

DirectSound™ 3 SW (not available on Vista)

 10-band Equalizer with 12 preset modes; 27 global environment effects

 Support 7.1 CH digital audio playback for Windows Vista, XP, 2K, ME, 98SE (Microsoft® DirectX V.9.0

above is required)

 WinCE driver and Linux OSS driver available

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CMI8768
PCI 8CH Integrated Sound Chip

3. Block Diagram

CMI 8768

ZV Port
DMA Engine
PCI Local Bus

& IRQ
Control
PCI S/PDIF I/O Digital I/O

Interface

8CH DAC
Audio
DSP Engine 2CH ADC

8CH Analog Outputs

HP AMP

PLL Analog
MPU-401 Line/CD/Aux Inputs
(14.318MHz) Mixer
Port
Microphone/PCBeep

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CMI8768
PCI 8CH Integrated Sound Chip

4. Pin Assignment

Top View of CMI8768

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CMI8768
PCI 8CH Integrated Sound Chip

5. Pin Description
5.1 Digital I/O

Pin No Signal Name Type Description

1-2, 5-7,

12-16,

19-21,

32-35,
XA31 – XA0 I/O PCI bus address and data lines
38-41,

43-44,

47-52,

126-128

117 XINTA O Interrupt request, active-low

119 XPRST I Reset

120 XCLK33 I PCI bus clock

121 XGNT I Bus master grant, active-low.

122 XREQ O Bus master request, tri-state output, active-low.

9 XIDSEL I ID select, active-high. (only work with A16~31 pin of host controller)

23 XFRAME I/O Cycle frame, active-low.

Initiator ready, active-low. The bus master device is ready to transmit
24 XIRDY I/O
or receive data.
Target ready, active-low. The target device is ready to transmit or
25 XTRDY I/O
receive data.
Device select, active-low. The target device has decoded the address
26 XDEVSEL I/O
of the current transaction as its own chip select range.
Stop transaction, active-low. The target device request to the master
29 XSTOP I/O
to stop the current transaction.
Parity. The pin indicates even parity across XA31-XA9 and XCBE3-XCBE0
30 XPAR I/O
for both address and data phases.
8, 22, 31, Multiplexed command / byte enable. These pins indicate cycle type
XCBE0 – XCBE3 I/O
42 during the address phase of a transaction.
88 XTXD O MIDI transmit data
89 XRXD I MIDI receive data
55 XIN I 14.318 MHz crystal input or ext. oscillator input
56 XOUT O 13.318 MHz crystal output or NC
87 XGBIO0 I/O General purpose I/O
84 XEECS O EEPROM chip select
85 XMBCSZ I Audio chip enable select (low:enable)
112 ZVCLK I ZV port clock
98 XSPDIFO O S/PDIF output (5V)
S/PDIF input 1 /
86 XSPDIFI I
ZV port LR channel clock
S/PDIF input 2 (TTL 5V) /
113 XSPDIFI2 I
ZV port data input

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PCI 8CH Integrated Sound Chip

5.2 Analog I/O

Pin No Signal Name Type Description

57,58 XSUROUTL-R O Back surround out L/R channel

59 EXTBASS I External bass input

62 XINTREF O Internal reference voltage (for testing purpose)

64,65 XADOUTL-R O Front out L/R channel

66,67 XADCFL-R O ADC S/H capacitors

68 XCNOUT O Center channel output

69 XBSOUT O Bass channel output

CD audio differential ground
70 XCDGND O
channel output
71,72 XCDL-R I CD audio differential L/R channel input

73,74 XREARL-R O Side surround out L/R channel

75,76 XLNL-R I Line-In L/R channel

77,78 XAUXL-R I Aux input L/R channel

79 XPCSPKIN I PC beep or mono input

80 XMIC I Microphone input

5.3 Power & Ground

Pin No Signal Name Type Description

4, 10, 18,

27, 37,
VDDIO I PCI I/O power pin (3.3V)
45, 100,

124

54, 115 VDDCORE I Core logic power pin (3.3V)

83 VDD5V I PCI I/O power pin (5V)

3, 11, 17,

28, 36,

46, 53, GND I Digital ground

82, 99,

116, 125

61, 81 AVDD I Analog I/O power pin

60, 82 AGND I Analog ground

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CMI8768
PCI 8CH Integrated Sound Chip

5.4 NC

Pin No Signal Name

63, 90-97, 101 – 111, 114, 118, 123 NC

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CMI8768
PCI 8CH Integrated Sound Chip

6. Electrical Characteristics
6.1 Maximum Ratings

Parameter Symbol Min. Max. Unit

Digital power voltage DVDD 3 3.6 V

Analog power voltage AVDD 3 5.5 V

Digital Input Voltage VIND -0.5 3.6 V

Analog Input Voltage VINA -0.5 5.5 V

Operating temperature range TO 0 70 C

Storage temperature range TST -40 125 C

Maximum power dissipation PDMAX 300 MW

6.2 Recommended Operation Conditions

Parameter Symbol Min. Typ. Max. Unit

Digital Operating Voltage DVDD 3.135 3.3 3.465 V

Analog Operating voltage AVDD 4.75 5 5.25 V

Operating Ambient Temperature TO 0 25 70 C

6.3 Power Consumption

Parameter Min. Typ. Max. Unit

Power Supply Current (Normal)
AVDD (5.0V) - 35 - mA
DVDD (3.3V) - 10 - mA

6.4 Digital Characteristics

PARAMETER Symbol Condition Min. Typ. Max. Unit

Input high voltage(PCI I/O) VIH 2.0 - VDD+0.3 V

Input low voltage (PCI I/O) VIL -0.5 - 0.8 V

Output high voltage VOH IOH=1.5mA 2.4 - VDD V

Output low voltage VOL IOL=-0.5mA 0.0 0.2 0.4 V

Input Leakage Current IIL 0<Vin<VDD -70 - 70 μ A

Output Leakage Current IOL -70 - 70 μ A

SPDIF IN input high voltage VIH1 2.6 - - V

SPDIF IN input low voltage VIL1 - - 2.4 V

SPDIF output high voltage VOH1 - VDD5V - V

SPDIF output low voltage VOL1 - GND - V

Input Pin Capacitance Cin - - 10 pF

Pin Inductance Lpin - - 20 nH

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PCI 8CH Integrated Sound Chip

6.5 AC Characteristics

Parameter Symbol Condition Min. Max. Units

High Clamp Current Ich Vdd+4>Vin>=Vdd+1 25+(Vin-Vdd-1)/0.015 - mA

Low Clamp Current Icl -3<Vin<=-1 -25+(Vin+1)/0.015 - mA

Output Rise Slew Rate SLEWr 0.2Vdd-0.6Vdd load 1 4 V/ns

Output Fall Slew Rate SLEWf 0.6Vdd-0.2Vdd load 1 4 V/ns

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CMI8768
PCI 8CH Integrated Sound Chip

6.6 Analog Performance

The measurements are performed under the circumstance as:
Tambient = 25℃, AVdd = 5.0V ± 5%, DVdd = 3.3V ± 5%, 10kΩ /50pF external load. Input is 1 kHz sine
wave; Sampling frequency = 48 kHz; Bandwidth = 20 to 20 kHz; 0dB attenuation; All sound effects
such as 3D effects are disabled.

Parameter Minimum Typical Maximum Units

Full Scale Input Voltage:

Line Inputs (Mixer) - 1.1 1.25 Vrms

Line Inputs (A/D) - - 1.25 Vrms

Mic Inputs (20dB boost) - 0.1 1.25 Vrms

Full Scale Output Voltage:

Front_Out - 1.1 - Vrms

Side_Surround_Out - 1.1 - Vrms

Center / LFE_out - 1.1 - Vrms

Back_Surround_Out - 1.1 - Vrms

SNR (Idle) -

A/A - 100 - dB

D/A - 101 - dB

A/D - 86 - dB

Dynamic Range (-60dB)

A/A - 100 - dB

D/A - 94 - dB

A/D - 85 - dB

THD+N

A/A - 0.005 - %

D/A - 0.017 - %

A/D - 0.015 - %

Frequency Response

A/A 5 - 22,000 Hz

D/A 5 - 22,000 Hz

A/D 10 - 22,000 Hz

Cross-talk @ 10KHz (A/A) - 100 - dB

Transition Band 19,200 28,800 Hz

Stop Band 28,800 ∞ Hz

Stop Band Rejection - -70 - dB

Out-Of-Band Rejection - -65 - dB

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CMI8768
PCI 8CH Integrated Sound Chip

Parameter Minimum Typical Maximum Units

Power Supply Rejection Ratio - -65 - dB

Master Volume Gain (32 steps)

Step Size 1.5 dB

Control Range -54 - +6 dB

Analog Input Gain (16 steps)

Step Size 2 dB

Control Range -30 - 0 dB

Mic Input Gain (16 steps)

Step Size 3 dB

Control Range -22 - +24 dB

Mic Boost Gain - +20 - dB

PCSPK Input Gain (4 steps)

Step Size 8 dB

Control Range -24 - 0 dB

Recording Gain (16 steps)

Step Size 1.5 dB

Control Range 0 - +22.5 dB

Input Impedance

Line-In, CD, Aux, PCSPK - 60 - KΩ

Mic (w/o Boost) - 30 - KΩ

Mic (w/ Boost) - 10 - KΩ

Output Impedance

Amplifier Output - 2 - Ω

Non-amp Output - 200 - Ω

Output Power
Line-Out (Front) @32Ω Load - 50 - mW
Line-Out (Front) @10KΩ Load - 0.16 - mW

Vrefout - 2.25 - V

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CMI8768
PCI 8CH Integrated Sound Chip

7. Mechanical Dimensions
QFP-128

Symbols Min. Typ. Max. Notes

A1 0.25 0.35 0.45 Jedec outline：N/A

A2 2.57 2.72 2.87 Datum plane H is located at the bottom of the mold parting line

b 0.10 0.20 0.30 coincident with where the lead exits the body.

C 0.10 0.15 0.20 Dimensions E and D do not include mold protrusion. Allowable

D 13.90 14.00 14.10 protrusion is 0.25 mm per side. Dimensions E and D do include

E 19.90 20.00 20.10 mold mismatch and are determined at datum plane H.

e - 0.50 - Dimension b does not include dambar protrusion.

Hd 17.00 17.20 17.40

He 23.00 23.20 23.40

L 0.65 0.80 0.95

L1 - 1.60 -

Y - - 0.08

θ º 0 - 12
Unit：mm

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CMI8768
PCI 8CH Integrated Sound Chip

－End of Specifications－

C-MEDIA ELECTRONICS INC.

6F., 100, Sec. 4, Civil Boulevard, Taipei, Taiwan 106 R.O.C.

TEL：+886-2-8773-1100

FAX：+886-2-8773-2211

E-MAIL：sales@cmedia.com.tw

Disclaimer:
Information furnished by C-Media Electronics Inc. is believed to be accurate and reliable. However, no responsibility is assumed by C-Media Electronics Inc. for its use, nor for any
infringements of patents or other rights of third parties that may result from its use. Specifications subject to change without notice. No license is granted by implication or
otherwise under any patent or patent rights of C-Media. Trademark and registered trademark are the property of their respective owners.

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