May 2008

ASM3P2187A/B

rev 0.2

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

PulseCore Semiconductor Corporation

1715 S. Bascom Ave Suite 200, Campbell, CA 95008

• Tel: 408-879-9077 • Fax: 408-879-9018

www.pulsecoresemi.com

Spread Spectrum Clock Generator for Mobile Applications

Features

•

Generates a 4X EMI optimized clock signal at the

Output.

•

Input frequency

: 12.5MHz to 20MHz

•

Output frequency : 50MHz to 80MHz

•

SSON/PDB option

•

Selectable Centre Spread :

± 0.5%, ± 1.0%

•

Low power CMOS design

•

Supply Voltage : 3.3V ± 0.3V

•

Industrial Temperature range

•

8-pin TSSOP Package

•

Drop-in replacement for MB88155-412 Device

Product Description

The ASM3P2187A/B is a versatile spread spectrum

frequency modulator designed specifically for a wide

range of clock frequencies. The ASM3P2187A/B reduces

electromagnetic interference (EMI) at the clock source,

allowing system wide reduction of EMI of

all clock

dependent

signals.

The

ASM3P2187A/B

allows

significant system cost savings by reducing the number of

circuit board layers ferrite beads,

shielding that are

traditionally required to pass EMI regulations.

ASM3P2187A device has an option of Spread ON/OFF

and ASM3P2187B device has Powerdown option

Application

The ASM3P2187A/B is targeted towards mobile phones,

mobile audio players and PDAs.

Block Diagram

VSS

CLKIN/XIN

SEL

REFOUT

Frequency

Divider

Feedback

Divider

Modulation

Phase

Detector

Loop

Filter

VCO

Output

Divider

PLL

VDD

SSON/PDB

XOUT

Crystal

Oscillator

ModOUT