MK2049-02/03

Communications Clock PLLs

MDS 2049-02/03 B

5

Revision 040601

Integrated Circuit Systems, Inc. • 525 Race Street • San Jose • CA • 95126 • (408)295-9800tel• www.icst.com

OPERATING MODES

The MK2049-02/03 have three operating modes: External, Loop Timing, and Buffer. Although each

mode uses an input clock to generate various output clocks, there are important differences in their input

and crystal requirements.

External Mode

The MK2049-02/03 accept an external 8 kHz clock and will produce a number of common communica-

tion clock frequencies. The 8 kHz input clock does not need to have a 50% duty cycle; a “high” or “on”

pulse as narrow as 10 ns is acceptable. In the MK2049-02, the rising edge of CLK2 is aligned with the

rising edge of the 8 kHz ICLK; refer to Figure 1 for more details. In the MK2049-03, the rising edges of

CLK1 and CLK2 are both aligned with the rising edge of the 8 kHz ICLK (unless noted in the shaded area

of the table); refer to Figure 2 for more details.

• 0 = connect directly to ground, 1 = connect directly to VDD.

• Crystal is connected to pins 2 and 3; clock input is applied to pin 13.

MK2049-03 Output Decoding Table – External Mode (MHz)

ICLK

FS3 FS2 FS1 FS0

CLK1

CLK2

CLK3

Crystal

8 kHz

0

0

0

0

1.544

3.088

8 kHz

12.352

8 kHz

0

0

0

1

2.048

4.096

8 kHz

12.288

8 kHz

0

0

1

0

18.688

37.376

8 kHz

9.344

8 kHz

0

0

1

1

7.68

15.36

8 kHz

10.24

8 kHz

0

1

0

0

19.44

38.88

8 kHz

9.72

8 kHz

0

1

0

1

16.384

32.768

8 kHz

8.192

8 kHz

0

1

1

0

24.576

49.152

8 kHz

12.288

8 kHz

0

1

1

1

8.64

17.28

8 kHz

11.52

8 kHz

1

0

1

0

12.416

24.832

8 kHz

12.416

8 kHz

1

0

1

1

18.528

37.056

1.544 MHz

12.352

8 kHz

1

1

0

0

10.24

20.48

8 kHz

10.24

8 kHz

1

1

0

1

4.096

8.192

8 kHz

8.192

ICLK

FS3 FS2 FS1 FS0

CLK1

CLK2

Crystal

CLK3

1.544

1

0

0

0

1.544

3.088

12.352

N/A

2.048

1

0

0

1

2.048

4.096

12.288

N/A

MK2049-03 Output Decoding Table – Loop Timing Mode (MHz) for T1/E1

ICLK

FS3 FS2 FS1 FS0

CLK1

CLK2

Crystal

CLK3

19 - 28

1

1

1

0

ICLK/2

ICLK

ICLK/2

N/A

10 - 14

1

1

1

1

2*ICLK

4*ICLK

ICLK

Low

MK2049-03 Output Decoding Table – Buffer Mode (MHz)

= No Zero (Fixed) I/O Delay for these selections shown in the shaded boxes.