DEVICE SETUP AND CONFIGURATION

CDCE421A

SCAS873 – APRIL 2009..................................................................................................................................................................................................... www.ti.com

Table 2. Crystal Frequency Selection and Device Settings

DESIRED OUTPUT

REQUIRED INPUT CRYSTAL

FREQUENCY (MHz)

FREQUENCY (MHz)

VCO

OUTPUT

PRESCALER

FEEDBACK

From

To

From

To

SELECTION

DIVIDER

SETTING

DIVIDER(1)

1020

1175

31.875

36.719

VCO 2

1

2

32

875.2(2)

1020

27.351

31.875

VCO 1

1

2

32

680

766.7(2)

34

38.333

VCO 2

1

3

20

583.5

680

29.174

34

VCO 1

1

3

20

510

587.5

31.875

36.719

VCO 2

1

4

16

437.6

510

27.351

31.875

VCO 1

1

4

16

408

460

34

38.333

VCO 2

1

5

12

350.1

408

29.174

34

VCO 1

1

5

12

340

383.3

34

38.333

VCO 2

2

3

20

291.7

340

29.174

34

VCO 1

2

3

20

255

293.8

31.875

36.719

VCO 2

2

4

16

218.8

255

27.351

31.875

VCO 1

2

4

16

204

230

34

38.333

VCO 2

2

5

12

175

204

29.174

34

VCO 1

2

5

12

170

191.7

34

38.333

VCO 2

4

3

20

145.9

170

29.174

34

VCO 1

4

3

20

127.5

146.9

31.875

36.719

VCO 2

4

4

16

109.4

127.5

27.351

31.875

VCO 1

4

4

16

102

115

34

38.333

VCO 2

4

5

12

87.5

102

29.174

34

VCO 1

4

5

12

85

95.8

34

38.333

VCO 2

8

3

20

72.9

85

29.174

34

VCO 1

8

3

20

63.8

73.4

31.875

36.719

VCO 2

8

4

16

54.7

63.8

27.351

31.875

VCO 1

8

4

16

51

57.5

34

38.333

VCO 2

8

5

12

43.8

51

29.174

34

VCO 1

8

5

12

42.5

47.9

34

38.333

VCO 2

16

3

20

36.5

42.5

29.174

34

VCO 1

16

3

20

31.9

36.7

31.875

36.719

VCO 2

16

4

16

27.4

31.9

27.351

31.875

VCO 1

16

4

16

25.5

28.8

34

38.333

VCO 2

16

5

12

21.9

25.5

29.174

34

VCO 1

16

5

12

21.3

24

34

38.333

VCO 2

32

3

20

18.2

21.3

29.174

34

VCO 1

32

3

20

15.9

18.4

31.875

36.719

VCO 2

32

4

16

13.7

15.9

27.351

31.875

VCO 1

32

4

16

12.8

14.4

34

38.333

VCO 2

32

5

12

10.9

12.8

29.174

34

VCO 1

32

5

12

(1)

Feedback divider is set automatically with respect to the prescaler setting.

(2)

Discontinuity in frequency range.

6

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