October 2006

P2560B

rev 1.3

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

Low Frequency EMI Reduction

Features

•

FCC approved method of EMI attenuation

•

Generates a low EMI spread spectrum and a non

spread reference signal of the input clock

frequency

•

Optimized for input frequency range from

20 to 32MHz

•

Internal loop filter minimizes external components

and board space

•

Two selectable spread ranges

•

3.3V Operating Voltage

•

Ultra low power CMOS design: 5.50 mA @3.3V

•

Supports notebook VGA and other LCD timing

controller applications

•

Available in 8-pin SOIC and TSSOP

Product Description

The P2560B is a versatile spread spectrum frequency

modulator designed specifically for a wide range of clock

frequencies. It reduces electromagnetic interference (EMI) at

the clock source allowing system-wide reduction of EMI of

downstream clock and data dependent signals. It allows

significant system cost savings by reducing the number of

circuit board layers and shielding traditionally required to

pass EMI regulations.

The P2560B modulates the output of a single PLL in order to

spread the bandwidth of a synthesized clock, thereby

decreasing the peak amplitudes of its harmonics.

This results in significantly lower system EMI compared to

the typical narrow band signal produced by oscillators and

most clock generators. Lowering EMI by increasing a signal’s

bandwidth is called spread spectrum clock generation.

The P2560B uses the most efficient and optimized

modulation profile approved by the FCC and is implemented

by using a proprietary all-digital method.

Applications

The P2560B is targeted toward the notebook VGA chip and

other displays using an LVDS interface, PC peripheral

devices and embedded systems.

Block Diagram

VDD

VSS

ModOUT

XIN /CLKIN

Frequency

Divider

Feedback

Divider

Modulation

Phase

Detector

Loop

Filter

VCO

Output

Divider

PLL

Crystal

Oscillator

XOUT