September 2006

PCS3P2189A

rev 0.1

Spread Spectrum Clock Generator

2 of 7

Notice: The information in this document is subject to change without notice.

Pin Configurations

Pin Description

Pin#

Pin Name

Type

Description

1

CLKIN / XIN

I

Crystal connection or external reference frequency input. This pin has dual

functions. It can be connected either to an external crystal or an external reference

clock.

2

XOUT

O

Crystal connection. If using an external reference, this pin must be left

unconnected.

3

SSON

I

Modulation enables pin. When HIGH enables spread spectrum modulation. Has an

Internal pull up resistor

4

S1

I

Spread range select. Digital logic input used to select frequency deviation

(Refer Spread Deviation Table). This pin has an internal pull-up resistor.

5

S0

O

Spread range select. Digital logic input used to select frequency deviation

(Refer Spread Deviation Table). This pin has an internal pull-up resistor.

6

VSS

P

Ground Connection. Connect to system ground.

7

ModOUT

O

Low EMI 4x clock output.

8

VDD

P

Power Supply Voltage Pin. Connect to +3.3V.

Spread Deviation Selection Table

S1

S0

Deviation

0

0

± 0.5%

0

1

± 1.0%

1

0

± 1.5%

1

1

± 2.0%

Modulation Enable Setting Table

SSON

Modulation

L

No Modulation

H

Modulation

6

S0

1

2

3

4

5

7

8

PCS3P2189A

CLKIN / XIN

XOUT

S1

ModOUT

VSS

SSON

VDD