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FUNCTIONAL DESCRIPTION

Zero ppm Audio and Video System Clock Generation and Divider Setting

27MHz

Crystal

CDC906

16.9344MHz(384fs)

33.8688MHz(768fs)

11.2896MHz(256fs)

27MHz

DVD−DSP

MPEG/AC−3

AudioDec

Karaoke

DSP

PCM1716

Front

Surround

Center

Subwoofer

CPUClock

64MHz

i.e.audiorate:44.1kHz

CDC906

SCAS828 – SEPTEMBER 2006

The CDC906 is ideally suited for audio and video applications. It consists of a triple PLL clock generator which

generates up to six audio, video and system clocks from i.e. a 27-MHz master clock. The output frequencies are

programmable to meet different application requirements. The master clock can be either a crystal oscillator or

an external input clock signal. The CDC906 provides a very low jitter, high accuracy clock with zero ppm for the

common audio and video clocks. The following table shows the system clocks versus the standard sampling

frequency and the corresponding divider settings.

Divider

Divider

Audio Rate

fs x 256

fs x 384

Error ppm

Error ppm

[kHz]

[MHz]

[MHz]

M

N

P

M

N

P

16

4.096

375

2048

36

0

6.144

125

768

27

0

22.05

5.6448

75

392

25

0

8.4672

125

588

15

0

24

6.144

125

768

27

0

9.216

125

768

18

0

32

8.192

375

2048

18

0

12.288

375

2048

12

0

44.1

11.2896

375

1568

10

0

16.9344

125

784

10

0

48

12.288

375

2048

12

0

18.432

125

768

9

0

96

24.576

375

2048

6

0

36.864

375

2048

4

0

Divider

Divider

Audio Rate

fs x 512

fs x 768

Error ppm

Error ppm

[kHz]

[MHz]

[MHz]

M

N

P

M

N

P

16

8.192

375

2048

18

0

12.288

375

2048

12

0

22.05

11.2896

375

1568

10

0

16.9344

125

784

10

0

24

12.288

375

2048

12

0

18.432

125

768

9

0

32

16.384

375

2048

9

0

24.576

375

2048

6

0

44.1

22.5792

375

1568

5

0

33.8688

125

784

5

0

48

24.576

375

2048

6

0

36.864

375

2048

4

0

96

49.152

375

2048

3

0

73.728

375

2048

2

0

NOTE: Input frequency is 27 MHz.

Video

Divider

Divider

Divider

2

Error

1

Error

0.5

Error

Rate

[MHz]

ppm

[MHz]

ppm

[MHz]

ppm

M

N

P

M

N

P

M

N

P

[MHz]

27

54

1

8

4

0

27

-

-

1

0

13.5

-

-

2

0

Typical applications for the CDC906 are digital HDTV systems, gaming consoles, DVD players, DVD add-on

cards for multimedia PCs, and step-top boxes.

Figure 14. CDC906 System Application Block Diagram

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