August 2005

ASM3P18S19B

rev 2.1

Notebook LCD Panel EMI Reduction IC

2 of 7

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

Pin Configuration

Pin Description

Pin#

Pin Name

Type

Description

1

XIN / CLKIN

I

Crystal Connection or external frequency input.This pin has dual

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

reference clock

2

VSS

P

Ground Connection. Connect to system ground.

3

SRS

I

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

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

resistor.

4

ModOUT

O

Spread spectrum clock output. (Refer Input Frequency and Modulation

Rate Table and Spread Deviation Selection Table)

5

REF

O

Non-modulated Reference clock output of the input frequency.

6

PD#

I

Power down control pin. Pull LOW to enable Power-Down mode. This pin

has an internal pull-up resistor.

7

VDD

P

Power Supply for the entire chip.

8

XOUT

O

Crystal Connection. Input connection for an external crystal. If using an

external reference, this pin must be left unconnected.

Input Frequency and Modulation Rate

Part Number

Input Frequency Range

Output Frequency range

Modulation rate

ASM3P18S19B

20MHz to 40MHz

20MHz to 40MHz

Input Frequency / 512

Spread Deviation Selection

Part Number

SRS

Spread Deviation

0

-1.25% (DOWN)

ASM3P18S19B

1

-1.75% (DOWN)

VDD

PD#

XOUT

REF

1

2

3

4

5

6

7

8

ASM3P18S19B

XIN/ CLKIN

VSS

SRS

ModOUT