April 2007

P1727

rev 0.2

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

PulseCore Semiconductor

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

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

www.pulsecoresemi.com

Low Power Notebook LCD Panel EMI Reduction IC

Features

• FCC approved method of EMI attenuation

• Generates a low EMI spread spectrum of

the input clock frequency

• Optimized for frequency range:

P1727X: 20MHz to 40MHz

• Internal loop filter minimizes external

components and board space

• 8 different frequency deviations ranging

from +/-0.625% to –3.50%

• Low inherent Cycle-to-cycle jitter

• 3.3V Operating Voltage

• Supports notebook VGA and other LCD

timing controller applications

• Available in 8 pin SOIC and TSSOP

• Qualified for Industrial Temp Spec.

(-40°C to +85°C)

Product Description

The P1727 is a versatile spread spectrum

frequency modulator designed specifically for a wide

range of clock frequencies. The P1727 reduces

electromagnetic interference (EMI) at the clock source,

allowing system wide reduction of EMI of down stream

(clock and data dependent signals). The P1727 allows

significant system cost savings by reducing the number

of circuit board layers and shielding that are traditionally

required to pass EMI regulations.

The P1727 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 result 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 P1727 uses the most efficient and optimized

modulation profile approved by the FCC and is

implemented by using a proprietary all-digital method.

Applications

The P1727 is targeted towards notebook LCD displays,

other displays using an LVDS interface, PC peripheral

devices and embedded systems.

Block Diagram

CLKIN

VSS

Loop

Filter

Modulation

VDD

Frequency

Divider

Feedback

Divider

Phase

Detector

VCO

PLL

PDB

Output

Divider

REFOUT

ModOUT