October 2003

P2027A

rev E

Alliance Semiconductor

2575, Augustine Drive

• Santa Clara, CA • Tel: 408.855.4900 • Fax: 408.855.4999 • www.alsc.com

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

General Purpose EMI Reduction IC

Features

FCC approved method of EMI attenuation

Provides up to 20 dB of EMI suppression

Generates a low EMI spread spectrum clock of

the input frequency

Optimized for 27 MHz operation

Internal

loop

filter

minimizes

external

components and board space

3 selectable spread ranges and 2 modulation

rate options

SSON control pin for spread spectrum enable

and disable options

Low cycle-to-cycle jitter

3.3V operating voltage

16 mA output drives

TTL or CMOS compatible outputs

Low power CMOS design

Supports digital camera and other digital video

and imaging applications

Available in 8 pin SOIC and TSSOP

Product Description

The P2027 is a versatile spread spectrum frequency

modulator designed specifically for digital camera

and other digital video and imaging applications. The

P2027 reduces electromagnetic interference (EMI) at

the clock source, which provides system wide

reduction of EMI of all clock dependent signals. The

P2027 allows significant system cost savings by

reducing the number of circuit board layers and

shielding that are traditionally required to pass EMI

regulations.

The P2027 uses the most efficient and optimized

modulation profile approved by the FCC and is

implemented in a proprietary all-digital method.

The P2027 modulates the output of a single PLL in

order to “spread” the bandwidth of a synthesized

clock and, more importantly, decreases 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 frequency generators. Lowering EMI by

increasing a signal’s bandwidth is called “spread

spectrum clock generation”.

Applications

The P2027 is targeted towards DSC market as well

as other imaging and digital video applications like

DVD and VCD players.

Block Diagram