PLL701-31

Low EMI Spread Spectrum Multiplier Clock

47745 Fremont Blvd., Fremont, California 94538 Tel (510) 492-0990 Fax (510) 492-0991

www.phaselink.com

Rev 11/28/05 Page 1

FEATURE

• Spread Spectrum Clock Generator with 1x

outputs.

• Output frequency ranges: 10MHz to 30MHz.

• Accepts input from crystal or reference clock.

• Selectable Center, Down or Asymmetric Spread

Modulation.

• Selectable Modulation magnitude.

• TTL/CMOS compatible outputs.

• 3.0V (+/-10%) Supply Voltage.

• Low short-term jitter.

• Available in 8-Pin 150mil SOIC.

DESCRIPTION

The PLL701-31 is a Spread Spectrum Clock

Generator designed to reduce EMI in high-speed

digital systems. The device is designed to operate

from a crystal or reference clock input and provides a

1x modulated clock output. Center, Down and

Asymmetric spread types are selectable as well as

the modulation magnitude.

PIN CONFIGURATION

Note:

^: Internal pull-up resistor (120k

Ω for SD, 30 kΩ for

SC0-SC2).

*: The value of SD is latched upon power-up. The

internal pull-up resistor results in a default high value

when no pull-down resistor is connected to this pin

(recommended external pull-down resistor of 27 k

Ω).

OUTPUT CLOCK SELECTION

SST Modulation

SD

SC2

SC1

SC0

Magnitude

Freq.

Type

0

1

1

0

3.75%

D

-3.75%

1

0

0

1

3.50%

D

-3.50%

1

0

1

0

3.75%

A

+0.125%, -3.625%

1

1

0

0

3.25%

D

-3.25%

1

1

0

1

3.50%

A

+0.125%, -3.375%

1

1

1

0

3.75%

A

+0.25%, -3.5%

0

0

0

0

3.25%

C

+/-1.625 %

0

0

0

1

3.50%

C

+/-1.75%

0

0

1

0

3.75%

C

+/-1.875%

0

0

1

1

0.00%

Fin / 512

SST OFF

Notes: A: Asymmetric Spread. D: Down Spread. C: Center Spread.

1

2

3

45

6

7

8

XIN/FIN

XOUT/SD*^

SC0^

SC1^

VDD

FOUT

GND

SC2^

XIN/FIN = 10 ~ 30 MHz