3.3V Communications Clock PLL

MDS 2049-45 G

3

Revision 101904

Integrated Circuit Systems, Inc.

MK2049-45

Output Decoding Table - External Mode (MHz)

Output Decoding Table - Buffer Mode (MHz)

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.

Functional Description

The MK2049-45 is a clock generator IC that generates

an output clock directly from an internal VCXO circuit

which works in conjunction with an external quartz

crystal. The VCXO is controlled by an internal PLL

(Phase Locked Loop) circuit, enabling the device to

perform clock regeneration from an input reference

clock. The MK2049-45 is configured to provide a high

frequency communications reference clock output from

an 8 kHz input clock or to jitter attenuate and buffer a

high frequency input clock. There are 14 selectable

output frequencies and two buffer mode selections.

Please refer to the Output Clock Selection Table on

Page 2.

Most typical PLL clock devices use an internal VCO

(Voltage Controlled Oscillator) for output clock

generation. By using a VCXO with an external crystal,

18

CAP2

Loop

Filter

Connect the loop filter capacitors and resistor between this pin and CAP1.

19

RES

-

Connect a resistor to ground. See table.

20

FS0

Input

Frequency select 0. Determines CLK input/outputs per table on page 2.

Internal pull-up resistor.

ICLK

FS3

FS2

FS1

FS0

CLK/2

CLK

8k

Crystal

Used (MHz)

N

8 kHz

0000

1.544

3.088

8 kHz

24.576

3072

8 kHz

0001

2.048

4.096

8 kHz

24.576

3072

8 kHz

0010

22.368

44.736

8 kHz

24.576

3072

8 kHz

0011

17.184

34.368

8 kHz

24.576

3072

8 kHz

0100

19.44

38.88

8 kHz

19.44

2430

8 kHz

0101

12.8

25.6

8 kHz

25.6

3200

8 kHz

0110

25.92

51.84

8 kHz

17.28

2160

8 kHz

0111

4.096

8.192

8 kHz

16.384

2048

8 kHz

1000

18.528

37.056

8 kHz

24.704

3088

8 kHz

1001

12.352

24.704

8 kHz

24.704

3088

8 kHz

1010

24.576

49.152

8 kHz

16.384

2048

8 kHz

1011

16.384

32.768

8 kHz

16.384

2048

8 kHz

1100

17.28

34.56

8 kHz

17.28

2160

8 kHz

1101

62.5

125

8 kHz

25

3125

Pin

Number

Pin

Name

Pin

Type

Pin Description

ICLK

FS3

FS2

FS1

FS0

CLK/2

CLK

8k

Crystal

N

20 - 50

1110

ICLK

2*ICLK

N/A

ICLK/2

3

10 - 25

1111

ICLK/2

ICLK

N/A

ICLK

3